You guys are overlooking the fact that this is a Judd Apatow written and directed movie, not some Adam Sandler, Chuck and Larry wannabe. Sandler and Apatow were actually college roommates at USC. This will be a great one, mark my words, but for very different reasons than Billy Madison, Happy Gilmore or even Punch Drunk Love (a personal fave of mine, but is in a field of its own).
Also people like the hate on Rogen a lot. Say whatever you want, but the man is a master of improv (along with many others in the Apatow crew)