Forza Horizon 3 had some amazing DLC! The Blizzard Mountain DLC brought snowy mountains to the Australian setting and The Hot Wheels DLC installed bright orange tracks and loop-the-loops over the ocean front.

I would love something similar to Hot Wheels again for Horizon 4 again. As for something new the series does a great job with wide open road racing, but besides Edinburgh, city racing is very rare. With that being said I would like to see them add another large city area in DLC to have more street style racing or just expand the existing Edinburgh area.

I would also love them to expand on the non-racing portions of the games, More businesses, housing customization, player customization maybe add a campy story you can play along with..but that may have to wait for Horizon 5.

Its time for them to add bikes.

@mems1224: I was actually going to say this as well. But I want a new area for the bikes as well.

An area where you can drive up the side of buildings and a couple of cars that transform as you level them up inspired by Crackdown 3.

The Hot Wheels DLC was cool at first but I found the actual racing and exploration of the island not as fun as regular Horizon because it really made the game feel extra-arcadey.

In terms of ideas for new DLC, with the seasonal changes already in the game I would think bikes might be one of the only options that they haven't done before.

I wouldn't mind seeing more themed, licensed cars in car packs. We have Halo's Warthog already and plenty of James Bond-related Aston Martins. Could we get a Tim Burton Batmobile? A Delorean that leaves fiery contrails in its wake (see: Burnout Paradise)? How about some of the thorny, brutalized desertrunners from Fury Road?

I don't have an extravagant vision for any of their larger expansions. For a while I kicked around the idea of building deforming/transforming circuit courses--a race that might transpire over a couple of laps, the topography of each lap a little different from the one before. This line of thinking was mostly inspired by their efforts with Storm Island in Forza Horizon 2. "Earthquake Alley," or something silly, could be the name of the expansion. I don't know.

One of the things these Horizon games could leverage again is a DiRT-style rally race, that point-to-point time trial run. That was something Playground implemented in the first game but never truly returned to, instead incorporating traditional rally racing more into the core race structure of the main game.

Transformers cause why not. Or better yet, Go Bots. Because of the rage that would ensue.

I would like to see them allow us to build our own courses through the world. I don't mean just blueprints but more of a track editor where you can choose the route to take and allow us to place a few obstacles like jumps. Horizon 4 is the only game in the series where I completed everything 100% because the world is just so fun to drive through. Even now with having done everything I'm just cruising around offroad without a goal. I would love to create a racetrack on top of the mountains in the NW part of the map.

Wales DLC with a focus on Rally cars?

Hovercrafts.

Maybe some specific Hill Climb races or (if it was possible) Green Laning - they're quite niche motorsport that have a reasonable following in the UK.

Seasonal traffic jams on the motorway and the approach to Edinburgh to make it feel more realistic?

But mostly hovercrafts.

One of the expansions should be playground games making their version of split/second. I’d buy that.

I want to surf on my car, do a kickflip on it, while smoking weed listening to a podcast.

The places in the UK I've been to. Fuck the Cotswolds.

Gibraltar could be small enough to be copied inch-for-inch into the game as DLC. Drag racing on the airport runway, hillclimbs up the rock and scenic drives along the shore. I mean it would be tiny, but kind of funny.

Also, a vehicular combat mode in the style of Blur with "EMP-rockets", oil spills and all that stuff.

micro machines, let me shrink my fancy car down and drive through a kitchen counter