What do you mean by "few"! There can be many more improvements. Lemme give you some examples of what should have been San Andreas already:
- Diving (just the animation)
- Scubagear
- Submarines
- Deltawing (aka hang-glider)
- children (brutal (!) )
- Animals (I'd like to run over mad cows)
- First person view on weapons (a better one) (and the ability to switch between views)
Any much more which I can't come up with right now.