They should have made it so that players who pick 7 season-careers have the option of having to be a test driver, etc. I understand they didn't bother with this originally because its fairly mundane and time-consuming for the average player, but at least let the hardcore out there have a fuller experience.
I don't really care what Davidson says about the real world, it would also be nice to completely customise the setups in the game. Ok, so a driver can't do that in reality, but surely they do plan the setup before hand? What if I don't like the setup the team have decided? I don't really feel its necessary to be realistic in this aspect, it sounds like lazy design to me.
The AI in general needs to be much harder like CE. I actually preferred the tough-as-nails wet weather AI in that game compared to the pathetic AI in 2010. It should not be this easy to win races in a Virgin in your first season, it wasn't easy to win with Super Aguri in CE (talking hardest difficult settings here)!
They also need to make the AI smoother. Its not especially immersive having the AI constantly do small little swerves all the time like they are lagging out or something. It just doesn't look good. The AI is just too erratic in its movements.
They need to fix Monaco and its rediculous barrier-physics. The barriers are far too bouncy and have weird glitches when you touch them that throw your car in the air. They also need to fix the tunnel as its just wrong.
The damage model needs vast improvement. I felt CE was a lot better. Rear wings need to break, there needs to be more types of mechanical failures.
They need to improve the "equality" of the online cars. There still feels like there is a difference between the cars when you set it to "Equal". CE just used to give everyone effectively the physics of the best car (I think it was the Renault?) with only the appearance of their selected car. 2010 seems to simply give everyone the same horsepower and downforce but the handling is still different.