I tried the demo on the PS3, both with the controller and the DF Pro wheel. Short summary: it's only marginally better than the original Dirt when it comes to the driving model. I put everything on the hardest and most realistic levels. Yes, you can slide more, drift slightly better and spin out slightly more easily. But it's not a huge improvement - I would say that the driving model is back to what it was for CMR4 on PC.
Although the Presentation does plenty to distract you, the graphics haven't changed all that much either. The cars are still very low-poly. The colors still look weird. There are a few nice effects, but overall the tracks are very static. Meh. It's a far cry from a game like Motorstorm 2, and in some ways that's understandable (long stretches of road to cover) but in other ways just really weird when you think about it. The tracks are very lifeless, the cars don't feel too good, the physics are boring, it's just ... not quite it.
If I had expected more, I'd be more disappointed. But right now, it's just as I expected: disappointing.