I'd like to see more dialogue as well. There's that bit in the first movie where Thor says "We are not your enemies, Banner! Try to think!" and it just seemed like the perfect moment for Hulk to respond with something like "Puny Banner isn't here right now."
I'm not saying I want him to be a chatterbox or anything around a bunch of people he doesn't like, but it would be nice to flesh the character out beyond roars and smashing (not that there's anything wrong with either of those things