Niko doesn't need to eat to stay alive and get fat. I always thought this was a dumb and pointless gimmick in San Andreas.
Oh look CJ can get fat lolz. So cool.
It should be kept simple as an alternative to gaining health. That's it. If I wanted this Sims like bullsh*t I'd play The Sims.
-Interiors make physical proportional sense to their exteriors. In San Andreas it used to make me cringe going into one of the random safehouses and finding out they were in no way proportional to their exteriors. Even GTA III and Vice City done a much better job. It's another one of those things where quality trumps quantity.
-No need for Hollywood star power to make the characters memorable. Since GTA IV has the best characters in the series its writing stands on its own.
-No pointless underwater diving ocean adventures. Swimming is all that's needed.