The aliens in Crysis 1 were too stupid for doing anything thratening to the player but roaring and screaming like BIG dinos, they just couldn't think with their brains.
2
In Crysis 1, you couldn't really use the nanosuite in efficient ways, --> crytek you will make it better in crysis 2 i can feel this =) New modules, the ability to mark dropped weapons to find them later again, and so much new stuff --> super.
3
Vertikal gameplay will definitely HAVE to be in crysis 2 --> think of all the big buildings, craters, canols, rooms, ... In a jungle, you will always run straight ahead or right or left, nothing up down and that's noobish plus BORING. I'm sure you will agree with me.
4
If the story of Crysis 2 would be the same sluggish and boring as Crysis 1, I would preorder the fairy tales book from the grimm brothers before I'd buy the game!
Please Crysis fans don't instist on doing everyting as it was in Crysis 1, don't be conservative. Innovation has to leave back old habits and make place for new, often much better and more stunning technology.