I liked GTAIVs realism though, that's why I would say more options to go mental, but not have them in the story. I'm playing Saints Row 2 at the moment, well, I started it. It seems a lot of fun, but it's technically poor, driving/running/shooting are all awkward. I much prefer GTAs euphoria physics quality - being drunk in the game was never more fun, shooting your own foot etc.
...and if you tell that to the kids of today, they wont believe you!