Sorry nub I totally missed this reply, I work on the MP side of things so I'm not sure about the decision behind the overgrown New York. Some people assume it was to make the lives of the artist's easier (lots of asset re-use) but it's been far from the case, everything's been made and re-made from scratch, it's been quite a mammoth task for both the SP and MP teams so far.
The multiplayer is partly what you would expect from a modern day shooter MP (COD, MOH, BF etc) but there's plenty of things unique about it that the Crysis universe has enabled us to implement. All the levels are designed largely around verticality for one, as the Nanosuit enables the user to sprint faster and jump higher and further than any normal person. It takes some getting used to if you're a COD player (as I am) but the parkour elements that it brings to the game are pretty awesome. Honestly I do think that if you're not a fan of that general type of MP then you won't find much to change your mind with C3, but it's worth giving it a go to find out I'd say
