The Mav's didn't make the playoffs last season - they pretty much sucked. That means they are even closer than us to being in rebuild mode.
I don't get why they would give up a top 15 pick (when pickes are so highly valued by young teams) in return for two guys who combined to average about 5 minutes per game last season.
I also don't get why Cleveland would give up AV, one of the better bigs in the league, in return for a not-very-productive big man who isn't big and has minimal potential (Bass) and a low pick middle ground first round pick. I've little doubt that Cleveland could get a much better offer elsewhere...Bass on his own is really not worth much as trade bait.
Besides, I'm not sure that AV is really the right player for this team. He's not much of a scorer and the last thing we need is injury prone big men...if we are going to take that route we may as well trade for Amare, who is a far better fit on a team like ours that is desperately lacking scoring