Not sure I would really like this much, it would loose it's feel, I've played a bunch of FPS IOS games and I can tell they're nothing compared to original games. You loose the entire atmosphere also, as it is much more easier to distract someone when they're on their phone that on a desktop.
Looks really nice! I Will be Buying this for my phone, as I really enjoyed Gta III and still do. I know of course it will be nothing like the console/desktop version, but it will still be a good game to play whilst I'm bored.