I know GTA3 was big, but they should make GTA4 even bigger, a lot more missions, more cityies, or a bigger city, multiplayer, better graphics, the ability to fly a plane properly!! I think a good idea would be a number of seperate story paths that can take place, depending on decisions made, that would give it so much more play time. I also like the idea of being able to organise your own gang, which would get bigger as the game progresses