More guns? Well, OK, there are only so few guns in the demo, but didn't you expect that already? As far as the full game goes, there are a lot of guns, actually. True, not as many as COD, but then again, most of the guns in COD aren't even used. People mostly use AK74u, Famas, Commando and MP5K. That's basically where it ends.
I think Crysis 2 has a very good amount of guns. There aren't too few, yet there aren't too many either. It's just enough.
It's always better to focus on better balance, than just adding a crap load of guns in the game.