The problem with looking at the teaser for graphics is this: EA. They are notorious for touching up trailers and screenshots. It certainly looks like it's in-engine but I wouldn't be surprised if they used some crazy prerender resolution and then did a lot of post processing.
I wouldn't say so at all, with this coming from DICE at least. BC2 was exactly like the trailers led you to believe. The only problem is their trailers are scripted to hell.