4. New wardrobe
While we like the fact that it's impossible to make Niko look like an idiot in GTA 4 we also understand that some people want to buy some Bermuda shorts, a Mexican hat and walk around bare-chested. If people want to dress Niko like a clown, why not let them? While we're not suggesting this would be the right way for Rockstar to go about it, releasing items individually as DLC would surely rake in the money.
3. More weapons
For a real-world game the weapons in GTA 4 are fine. Using the RPG is great fun, but a few more over the top weapons would be great. We fancy knuckle dusters, a chain-gun, chainsaw and flame thrower, but Rockstar will hopefully be able to think of far more. Seeing how the people of Liberty City like to get on with their lives, wandering about as if real people, some remote mines would also go down very well indeed. We can only imagine how great it'd be to detonate a mine just as a swarm of police cars came hurtling down the road towards you. Evil, but good fun.