According to
IGN (I know, geez...), Wi-Fi still hasn't been decided on. They're "exploring options," but it may turn out to be just item-sharing or something equally of no interest to me (when compared to full wi-fi coop, at least)...
Bah, but it's not good news. I had a bad feeling about it.
P.S. - Does anyone else think it's a cop-out to say "We want you to be in the same room as the people you're playing with so you can talk to each other"? HELLO VOICE CHAT FRICK.