I'll start by saying that I really loved Oblivion, have put dozens if not hundreds of hours in it and consider it a great game all in all. That said, it had a lot of "problems", and, IMO, was far from being as great as Morrowind was. So here's my wishlist of what I'd like to see in V: 
 
- Seasons; every Elder Scrolls game to date have used the same cycling calendar. Time progresses while playing and sleeping, and you can tell what day, month and year it is by checking your journal. In Skyrim, why not take the concept to the next level? Introduce full seasons into the mix. Spring, Summer, Autumn and Winter. The Elder Scrolls is exactly the game that would benefit from this kind of treatment. The immersion would simply be even greater. 
 
- Disable leveling for enemies; or at least modify the formula so the player can have a feeling of immense power when reaching the later levels and after getting the better equipment. Morrowind had that; Oblivion, not. 
 
- More NPCs; the towns in Oblivion felt almost lifeless. There were not enough NPCs to fill them. They should do what they did in Fallout and take it to the next level: have a LOT of unimportant NPCs wander around town. The kind that don't require voice acting. I'm talking about the NPCs with no names who only give random lines of dialogues when you interact with them. I'm sure the new engine will be powerful enough to handle lots of NPCs; not to mention that computers are way more powerful than 5 years ago. I believe that the world would feel a lot more alive, and the game would benefit from that.
 
- Hardcore mode; a lot of Morrowind purists like myself were put off by the mainstreaming of Oblivion. I'm refering mainly to instant fast travel and the compass arrow. Yes, one could have simply never used fast travel and yes, one could have disabled the arrow in the settings, but this is not the same. Developers build their games around a set of features that are intended to be used in their entirety by the player. Morrowind had intradiegetic fast travel and it was limited; one couldn't simply open the map and pick a spot where to be instantly teleported. You had to find a silt strider so it could take you to a select number of spots. It didn't take you out of the immersion. Regarding directions, as the arrow wasn't present, whenever the player needed to go to a specific place, say, a house, the set of directions would be written in your journal (ex.: go to the second house past church). I want Skyrim to have a hardcore mode similar to New Vegas', which disables the fast travel and the compass arrow in addition to making you eat, drink and sleep. Immersion all the way. 
 
- No constant blocking; combat in Oblivion is what turned me off the most. You had to constantly guard until the enemy struck you, then you struck him, then you guard until he struck you again, and on and on and on. Ugh. Just make it so the shields add passive points to your overall defense, like any normal RPG. 
 
- More diversified environments; Oblivion basically had the same forest all around the province, except for a select few spots. Morrowind, on the other hand, had drastically different environments all across the island. Skyrim needs to be like that. 
 
- Less copy-pasta dungeons; seriously...

" - No constant blocking; combat in Oblivion is what turned me off the most. You had to constantly guard until the enemy struck you, then you struck him, then you guard until he struck you again, and on and on and on. Ugh. Just make it so the shields add passive points to your overall defense, like any normal RPG. "

A good or at least decent story.
Characters with personality.
Scale (for example:The Imperial City not being a somewhat-big circle with a hundred people in it)
Static levels.
More numerous and more interesting factions (like the great houses of Morrowind).
More varied spells (levitation ftw).
More and better animations.
Better physics.
Characters that doesn't look like aborted fetuses.
A good or at least decent character creator.
Beards!
Less bugs.
Good or at least decent writing.
More Dwemer-related things.
More and more interesting loot.
More and more interesting quests.
More voice actors.
No Oblivion gates.
Better conversations.
More stable construction set.
More varied and more interesting locations.
Better combat.
More immersion.
Bring back the Morrowind style equipment (gloves and pauldrons being separate, etc.)
More hairstyles.
NO ADORING FAN
More varied enemies.
Bring back the roman legion style imperial armors.
More racism (elder scroll races).

I would really like them to bring back levitation, and have puzzles in optional dungeons that require levitation.  That would be cool.
Puzzles that required telekinesis could be awesome too.
Better character face art would be fantastic.  Just dump Facegen, please.
Have some level scaling but some areas with dangerous beasts that will make adventuring more interesting.
Randomized high level loot would be pretty awesome.
Seasons would be spectacular but that's asking a lot.
More voice actors would be excellent.  There's little reason to have 5 different actors saying the same exact lines so often.
Tied into levitation, no load times upon entering a city / town.  Extending that to buildings would be even better still.  Other RPGs / open world games handle that just fine. 
Variety in environments is damned important.
 
That's what I can think of for now.

Seasons would be really cool. More varied environments than just caves and hellscapes. also DRAGONS! A lot more enemy types. More interesting alchemy. More dialogue and story heavy sidequests. Beautiful graphics. Women that look like women. More than 8 total voice actors for non essential npcs. 

The ability to customize your character's body as well as face. I want my viking to be fucking huge.  
 
Also, the ability to change appearance throughout the game, either involuntary (scaring, aging) or voluntary (tattoos). 

Crafting...think of it like alchemy with random objects. 
 
Since Skyrim is just north of Bruma i wonder how much diversity we're going to see in a place that's primarily ice and snow.

I actually kind of hope that any dragons in the game are both epically large and rare. I always thought it would be cool in Oblivion if there had been one or two unique, epic encounters (kind of like the invisible troll in the mountains- where you found the journal describing it and then could run into and kill it).

• I want a diverse range of voice actors rather than the four or five I heard throughout Oblivion. 
• Characters should remain consistent. For instance, I would talk to a woman who would speak in a voice and I would then speak to her again mere seconds after and she'd have a different voice actor!

Some good ideas in here that I agree with. I'd love to have better combat like most, it needs to be more engaging. When playing Oblivion I didn't mind the combat too much but thinking back... it was a bit tedious.  Ranged combat was very weak in Oblivion, crossbows would be a good addition to the game. 
 
I just loved the whole explore the world, find something interesting that told a story to share with my friends whilst coming out of it with something decent, be it a good bit of loot or something. I hope they don't add Multiplayer, I want them to just concentrate on the singleplayer experience. Also, I found after a few hours currency didn't become a problem at all in the game, being able to pick anything up and sell it, gave the possibility to make a lot of money fast. I hope the higher level weapons and equipment, cost a lot more than they priced them at.

I want to the name of the game to be changed to Skyrimjob. That would rule.

Better graphics, better animation so they don't look like robots and also better textures.

Make stacking shit possible again. Other than that I don't give a shit. Bethesda knows what they're doing.

" 
- No constant blocking; combat in Oblivion is what turned me off the most. You had to constantly guard until the enemy struck you, then you struck him, then you guard until he struck you again, and on and on and on. Ugh. Just make it so the shields add passive points to your overall defense, like any normal RPG. 
"

No more broken promises and lore retcon and I'll be happy.
 
Also, do away with Oblivion's leveling system and constantly leaping enemies.
Weather as a game mechanic should become a bigger part of the game (use wind to extinguish candles, fur protects more against the cold, etc).

If they made Oblivion again and made it look and play nicer, I'd be happy. and that's probably roughly what they're going to do,  new mechanics be damned.
 
And seasons are a monumental task, I'd much rather have them focus on more important matters. Same deal with voice actors.

They need to tweak the leveling system to discourage cheesing and metagaming, perhaps also adding some more complexity into the mix.  Maybe go back to like... 6 weapon classes again too? Spears are cool, right? Just don't dumb it down.
Make combat better. How? I don't know. But I don't want to play "block until they hit you, then hit them back" or "Just use VATS".
Either totally remove or severely reduce the amount of level scaling voodoo that goes on. 
Do the Morrowind thing of having to make choices between factions. I don't know, but having a character be the head of all the major guilds seems kind of ludicrous. Also, it encourages multiple playthroughs. 
On that note, better roleplaying options with more choices. Morality meter optional, if only because the choices are always so blatantly black and white.
Make being a pure mage worthwhile. Seriously.  
More varied and interesting environments. Self explanatory.

Hotdamn, I forgot these two: 
 
- Region-dependent bounties; you know how in both Morrowind and Oblivion you could steal an item in the most backwater village of the province, and by magic every goddamn guard in the entire province knew of your crime? This is a blow to the immersion, not to mention that it's completely farfetched, considering telecommunications don't exist. Skyrim needs to have bounties tied to a specific region only. If I steal a sword in Bruma, then my crime needs to be known only in Bruma and maybe a small radius around it.
 
- NPCs shouldn't know what good is stolen or not; Oblivion made it impossible to sell stolen goods. Only a small handful of people would buy that. It's just ridiculous; how can they know my shit is stolen? Seriously. Again, it breaks the immersion.

- NPCs shouldn't know what good is stolen or not; Oblivion made it impossible to sell stolen goods. Only a small handful of people would buy that. It's just ridiculous; how can they know my shit is stolen? Seriously. Again, it breaks the immersion. "

"  NO ADORING FAN "  

" This was the one thing that bugged the crap outta me about Oblivion. Obviously, if you were to sell the stolen item to the person you stole it from, it makes sense, but taking an item across the entire continent to someone who knows no history about the item should be able take it. "

I think it would be cool if the people in the world weren't so ugly, its kind of a petty thing but when you are playing a game for hours and hours and hours you don't really want to be looking a gross looking characters, ya know?

" @TheSeductiveMoose said:

"  NO ADORING FAN "  

Monster! "

Other than some of the other good ideas listed so far (seasons, combat improvements, NPC interactions, varied locations) the one thing I REALLY want is MORE MORE MORE ways to customize my character.  I want to look either like the most unique/sexiest woman or the most bad@$$/suave hero (man), lol.  More hairstyles, tattoos, scars, clothing, etc.  If there was a way to like implement armor or defense in a different manner so that I could constantly wear NORMAL, COOL looking clothes and not have to worry about getting killed in combat, that would be tight.  Some robes looked cool and had different properties sometimes (e.g. feather, intelligence, alchemy boosts) but you couldn't wear them in combat unless you had a death wish.  Basically what I want is MORE CUSTOMIZATION.

I hope they make the combat much more entertaining or interesting. Combat in Elder Scrolls bores me to death. 'Goes to install Oblivion'

I'd hope Bathesda learns what the word "immersion" means because I have yet to play a game from their studio that understands that concept.  All their games have been so completely devoid of charm, and are so steeped in the uncanny valley that I can't go 4 hours without popping the disc out of my xbox, shoving it into a dark, shameful corner, never to be seen again.

- Less copy-pasta dungeons; seriously... "

- Hardcore mode; a lot of Morrowind purists like myself were put off by the mainstreaming of Oblivion. I'm refering mainly to instant fast travel and the compass arrow. Yes, one could have simply never used fast travel and yes, one could have disabled the arrow in the settings, but this is not the same. Developers build their games around a set of features that are intended to be used in their entirety by the player. Morrowind had intradiegetic fast travel and it was limited; one couldn't simply open the map and pick a spot where to be instantly teleported. You had to find a silt strider so it could take you to a select number of spots. It didn't take you out of the immersion. Regarding directions, as the arrow wasn't present, whenever the player needed to go to a specific place, say, a house, the set of directions would be written in your journal (ex.: go to the second house past church). I want Skyrim to have a hardcore mode similar to New Vegas', which disables the fast travel and the compass arrow in addition to making you eat, drink and sleep. Immersion all the way

More variety in the voice acting would be nice, as after 70 or so hours you start to recognise the same voice actors for different characters. Also different looks to the tombs, more A.I's around citys and seasons would be great. Oh, and better combat and horse control.  
 
(better horse armour would also be great)

New game engine - Confirmed
Dual wield weapons 
Halbereds, spears and crossbows
Blood, gore and dismemberment 
Finisher moves and cinematic scenes
Stealth kills
A better level system  
Better crafting, spell and skill system
No fast travel, but instead replaced with several stations fitting the setting 
More mounts, not just horses 
Hardcore mode (Starvation, dehydration and sleep, all affects your health) 
More factions  
Everyone got voice acting, including your character  
Bigger arena fights 
More armors, including unique and set armors, and a better variety of them so they all dont look the same  
Color coding on items 
Option to have companions and to give them orders 
Better character creation system. Bring us BEARDS! 
Dynamic sound and music system 

I want to be the bad guy.
 
Also, I'd like for the leveling system to be tweaked so that I don't need to job it.  I don't like that there's a right way and wrong way to level in Oblivion (seriously, I wrote a damn guide about it), and that they combined so many different skills and weapon classes to simplify the game.  There's nothing wrong with complexity in the game design, as long as there is a rational and clearly defined way to power up your character in such a way that is rewarding and fun.  Who wants to jump 1000 times just to increase their stats? 
 
As for combat, I'd like to see them use Fallout's concept of limb damage, so that I can strategically take out an enemy's leg or weapons.

I for one would be really bummed out if they remove fast travel.  I understand why some people don't like it, but when playing in a game with a huge world, I don't want to be bothered with running halfway across the map to find a silt strider.  I enjoyed exploring the wasteland in Fallout and I enjoyed wandering around the world in Oblivion, but there were times when I just want to move quickly.  
 
I second the motion for beards though.

Really just add more voice talent. I expect stuff like less bugs and a great graphics engine already.

Most of the things i want are already listed so here are the one's that arent.
Skill leveling needs to be better.
Eating animation's for your character.
Be able to Dance.
Improve the PS3 version Fallout has been very inferior on PS3.
Peeing and popping with animations.
Better way of talking with body language and stuff, they look like robot's when talking.

If they just gave me New Vegas that never crashed and without glitches I'd be pretty stoked!

That being said I played about 40 hours if Oblivion and I never got into it as much as Fallout 3 and New Vegas.

I think that what was missing for me was a levelling system more akin to that of Fallout's, and more weapon options! Collecting weapons and armor is great fun!

Also, more voice actors. Less persuasion mini-games.

Better character creator.

...and to top it all off, I would love me some VATS. The best part about that is if you don't enjoy VATS, you don't even have to use it. Bring on TES:V, I'm ready!!

A whole lot of stuff has been covered already so what I really want that no one has has said yet is straps and two handed sheaths. Look at red dead and how every piece of gear has something adhering it to johns body. My pie in the sky hope is that this "new engine" is gamebryo with  euphoria for its character animations.

I know this is against the core design philosophy of the Elder Scrolls series, but I REALLY want it to have a multiplayer option so that I can team up with my friends in Tameriel and explore dungeons together.

coop?

" A good or at least decent story. Characters with personality. Scale (for example:The Imperial City not being a somewhat-big circle with a hundred people in it)Static levels. More numerous and more interesting factions (like the great houses of Morrowind).More varied spells (levitation ftw). More and better animations. Better physics. Characters that doesn't look like aborted fetuses. A good or at least decent character creator. Beards! Less bugs. Good or at least decent writing. More Dwemer-related things. More and more interesting loot. More and more interesting quests. More voice actors. No Oblivion gates. Better conversations. More stable construction set. More varied and more interesting locations. Better combat. More immersion. Bring back the Morrowind style equipment (gloves and pauldrons being separate, etc.) More hairstyles. NO ADORING FAN More varied enemies. Bring back the roman legion style imperial armors. More racism (elder scroll races). "

I am sure that Bethesda has learned a lot from Fallout 3 and New Vegas, and will apply this newfound knowledge to good use in Skyrim. That said, here's another addition that my little finger is telling me we are bound to see in TES:V: 
 
- Perks; yeah, Fallout-style perks. The Elder Scrolls never had those; they've only been limited to Attributes and Skills. I am sure that this Fallout feature will bleed into Skyrim.

Aside from the stuff I have on my blog...
 
Considering that it's in Skyrim, I'd like there to be dynamic snow, in the same way that Spec Ops: The Line and Journey have sand. After a snowstorm, I want there to be drifts, and have it be harder to walk unless I cast a fire spell to melt it.
On the note of fire, Far Cry 2 style fire mechanics would be brilliant. It ain't gonna happen, but a guy can wish, right?
Also, a "cold mechanic" similar to the Fallout Rad mechanic. All clothing you wear has a certain heat rating. If your heat rating is not enough to compensate for the temperature, then you're not as fast, and could eventually die.  That might only be on a Hardcore mode, though.
Oh, and finally: combat. Now, I don't have as big an issue with Oblivion's combat than some people do, but playing it again over the weekend...strategy. Please, have a little more depth. Oh, and I want to be able to kick people. That would be awesome.

pillow stacking

" Also, a "cold mechanic" similar to the Fallout Rad mechanic. All clothing you wear has a certain heat rating. If your heat rating is not enough to compensate for the temperature, then you're not as fast, and could eventually die.  That might only be on a Hardcore mode, though. "

I mainly just want the new engine not to be buggy. I'm not terribly confident that will happen though. Pretty much everything else is gravy.

" @sfighter21: I think that in Oblivion you could alchemize cool looking items with properties you like. I believe I had a set of armor where I maxed out strength and put an bunch of featherlight spells on it so I could carry a ton of items.  Additionally,  I'd like to see a different set of conversation tools; something akin to Mass Effect's wheel. I enjoyed the seamless way the conversations flowed in ME 1 & 2. "