UFC 2009 Undisputed is a great game. But there are a lot of things that they NEED to add to the next game to make it a perfect MMA game. Here are just a few of those features:
 

• "Flash Submissions"- basically changing the way you pull off submissions. Basing it more on timing than on button mashing or rotating the right stick
• Cage integration- making it more than just a barrier; ex. leaning opponent against it
• More venues
• Career mode enhancements (THQ is pretty good with storylines in Smackdown)
  
• more fluid animations and make more animations so that they are not recycled for every fighter
• List of generic last and first names for CAF so that the announcer can say an actual name along with a nickname
• more nicknames
• more rocked/KO animations
• walk out entrances
• more blood
• custom banners for CAF
• TUF?
• post fight interviews for career
  

UFC 2009 Undisputed is a great game. But there are a lot of things that they NEED to add to the next game to make it a perfect MMA game. Here are just a few of those features:
 

• "Flash Submissions"- basically changing the way you pull off submissions. Basing it more on timing than on button mashing or rotating the right stick
• Cage integration- making it more than just a barrier; ex. leaning opponent against it
• More venues
• Career mode enhancements (THQ is pretty good with storylines in Smackdown)
  
• more fluid animations and make more animations so that they are not recycled for every fighter
• List of generic last and first names for CAF so that the announcer can say an actual name along with a nickname
• more nicknames
• more rocked/KO animations
• walk out entrances
• more blood
• custom banners for CAF
• TUF?
• post fight interviews for career
  

they do have flash subs already

Yeah, cutting down on loading times and streamlining the entire menu system. Otherwise I think you covered it.

yea, you pretty much covered everything.  
I just hope THQ improves on there cons. For example, each time a new Smackdown game comes out, I truly feel nothing has improved.
Hopefully, THQ (if not already) will recognize their cons and work on them.     

I want a better career mode mainly. More blood would also help.

There was only one thing stopping me from buying Undisputed, flash knockouts.. They happened wayy too often. A dealbreaker for me.

" There was only one thing stopping me from buying Undisputed, flash knockouts.. They happened wayy too often. A dealbreaker for me. "

Didn't know that, I already bought Fight Night Round 4 anyway though. Did the patch fix the rage-qutting problems aswell?

Cool, they needed to sort that out.

I disagree with some of those. More venues is kind of pointless IMO, and both pre-fight entrances and postfight interviews would be the kind of thing I would skip after the first few times. Cage integration, flash subs, TUF would be great, redone menus a must. 
 
I would also say fighter-specific moves are a must, such as Lyoto Machida's headkick should be different than everybody else's. Chuck Liddell's punches the same, etc.
 
Also I'd like to see WEC stuff, but probably not gonna happen

" @PhaggyBigNastyMcKill: how? "

6.        UFC 2009 UNDISPUTED             [FL00]  
-------------------------------------------------------------------------------
          Flash Submissions: Reversing Slams and Throws


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Flash Submissions: Reversing Slams and Throws 
---------------------------------------------

If you ever played as a Wrestler or a Judo practitioner, you obviously tried 
slams and throws from the clinch to get the opponent on the ground. If you 
played online or on higher difficulty levels (advanced or expert), I assume 
you've been caught at least ONE time in a Flash Submission. I got caught in a 
Flash Sub the FIRST day the DEMO came out...

There are two kinds of Flash Subs:

-Guillotine Choke by reversing a Wrestler's BIG slam.

-Rear Naked Choke by reversing a Judo Throw.

If you NEVER use BIG slams and Judo Throw, you will never get caught in a 
Flash Sub. Unfortunately, BIG slams and throws are awesome and it's very hard 
to refrain from using them...

There is no easy way to prevent a Flash Sub: if you ever try a BIG slam or a 
Judo Throw, you CAN get caught in a Flash Sub. You might be able to stop the 
slam or Thow before being reversed, but I only saw the CPU do it, I can't do
it myself. [V1.01]

What is even more annoying is that Flash Subs are VERY effective: I would say 
75% chance of success. If you attempt a BIG slam or a Throw with low stamina 
and get caught in a Flash Sub, you WILL Tap Out in no time!

Many people think they just been cheated by a Turbo Controller user. NO!

You just were fool enough to attempt a BIG slam or Throw against an expert 
player. The only way I know to escape a Flash Sub is to start mashing buttons 
AS SOON as you see you've been countered. If your stamina is still good, you 
might just succeed your escape if you mash buttons quickly.

Notice I said "mashing" buttons. That's right, you better mash buttons to 
escape a Flash Sub: no fancy Shine Method UNLESS you are a Sub Machine with 
low strength. BJJ expert don't have slams or Throw so they CAN'T get caught 
in a Flash Sub.

Let's begin by learning the difference between normal Slams, BIG Slams, Judo 
Trips and Judo Throws.

" I disagree with some of those. More venues is kind of pointless IMO, and both pre-fight entrances and postfight interviews would be the kind of thing I would skip after the first few times. Cage integration, flash subs, TUF would be great, redone menus a must.   I would also say fighter-specific moves are a must, such as Lyoto Machida's headkick should be different than everybody else's. Chuck Liddell's punches the same, etc.  Also I'd like to see WEC stuff, but probably not gonna happen "

They need to add the "UFC Only" option back into the Ranked Match search screen. It's complete bullshit they took it out with the patch.