The guys on the carrier aren't that bad, once you take out the minigun. I too used a couple of flashbangs, and kept moving from box to box. Plus that "lean" function really comes in handy.
The vehicles are a little so-so in their control, but they're no worse than those of any older console game. In a game like Far Cry I'll let sloppy vehicle control slide, but the more sim oriented Joint Ops had better improve it. The hang glider is just too cool for words, though. I'm going to have to replay that level just to see where I can go with it, instead of simply going from point A to point B.
Those beasties in the intro (which is completely different from what the early trailers had shown) do indeed show up later on. I haven't really fought more than one or two (and that was at medium range) but I forsee them being tough. I do like the soundtrack of the intro and the game, however.