Spoelstra will probably get the 'bright' idea of putting Joel Anthony on Dirk at some point early in the series, and I honestly think that would play right into the Mavs' hands. Anthony's nose for loose balls won't be quite as effective when he's chasing Dirk around the perimeter, and it would give Dirk yet another matchup where he only has to play on one end of the court. From Miami's perspective, Bosh needs to stay on Dirk. Unlike Ibaka and Collison, Bosh will make him play defense, so Dirk won't be able to rest in between possessions.
Dallas will miss Butler in this series. Marion and Stevenson are both solid defenders, and Brewer can chip in some valuable minutes, but I think they're one good wing defender away from being an excellent foil to the Heat.
I hope I'm wrong, but foul trouble will likely define this series. Chandler, Haywood, Marion and Stevenson need to stay on the court.
This feels funny to say, but I think Barea could wind up being the X-factor. I don't see anybody on the Heat bench who is really capable of keeping him out of the paint. If he's allowed to do whatever he wants, then the Mav bench will go off.
My gut tells me that Miami is just too athletic, but as I mull the matchup over in my head, I'm really starting to think that Dallas has a shot at this. This isn't the turnover-prone, fourth-quarter-fearing Celtics. This isn't the one-dimensional Bulls, either. Dallas moves the ball as well as anybody in the league, and the Heat could very well shut Dirk down in one game and still end up getting shot out of the building by some combination of Terry, Barea, Kidd, Marion, Peja and Chandler.
Still, I'm going to say Miami in 7.