Actually, it would be better to do one game per city, like they have recently done. That means more games for us to play. Think about it:
1 Game: About 2 years from now, and probably a 1 playing it. That's around 3-4 more years of playing GTA.
Add another game, 2-3 years of developing, and about 1 year playing it. That's another 3-4 years.
And yet another game. You get the drift, another 3-4 years playing it.
That's around 3-4 more years playing GTA VS. 9-12 more years of GTA. Which one sounds better NOW?