I loved Crysis 1, but I also loved Crysis 2. I thought it was the best single player FPS available at the time, and judged on its own merits was an awesome game. It's only when compared to the promise that the first game set up that it was a letdown - making the environments so much smaller was a big step backwards. One of the things I think the second did a lot better though was the Nanosuit, it had everything the first one had but made it much more streamlined. I tried playing through the first again, and I wish its Nanosuit controls were like number 2. Also, the aliens were generally much more enjoyable to fight in number 2, even if they did miss out on having the really gigantic ones.
Imagine if they'd stuck to PC throughout though; Crysis 3 was still set in an overgrown New York, but the levels were as expansive as the first game, where you could hop in a VTOL and fly for miles while the ground teemed with Ceph and CEL fighting it out... that would be something to see, shame it won't happen.
Looking forward to number 3!