The multiplayer is very very similar to Reach. Because it's built off the same engine. It's still cool though. I haven't played the Campaign so can't comment on that.
Good way to start on the forums. Smooth.
Jetpack makes you extremely vulnerable. As soon as I see someone in the air, I start shooting. That = 1 easy kill for me.
I don't think it will happen. Not in the foreseeable future anyway. People will always like the feel of a controller in their hands, and playing on a TV, etc.
Because Living dead contains many "younger" or "clan-susceptible" players. That's just the way it goes. You won't find that many players willing to join a clan in, mlg ffa, for example. Just a generalization.