Heh, I just recently revisited Crysis Warhead and wondered what happened to the cool singleplayer (okay, the alien sections suck) and the nanosuit. It is so fun to use a proper speed mode to quickly move from one place to another and find whacky ways to kill the enemies.
I liked some of the story ideas in Crysis 2 but the way the plot was delivered made it boring. "Here, let us say something important about the Nanosuit while you're bored at staring at the Nanosuit. Oh, you want to see something interesting? Watch someone have a long monologue, which feels weird because he talks to you but your character can't talk back." Acting like Gordon Freeman didn't help the story at all.