Mark Cuban and the Mavs are playing the disrespected card, while Pat Riley and the Heat know they haven't won anything yet, which makes for intriguing stories all around.
The first big storyline, how can the Mavs stop Shaq? Well, there's a couple ways. One, they've got the big bodies to bang with him down in the post, namely Desagana Diop and Eric Dampier. But the most effective way to take Shaq out of the game is to get him in foul trouble. Of course, getting someone into foul trouble is never as easy as it sounds, but the Mavs have the capability of doing this because they should be able to get to the rim all day against the slower Heat defenders on the perimeter, leaving them driving against Shaq, who's bound to commit fouls sometime on the defensive end. If they do that, it takes away the equalizer the Heat have.
The second question, how can the Mavs stop Dwyane Wade? After all, he's arguably even more dangerous than Shaq Fu. Once again, the Mavs have a multitude of options, a testament to their depth. Adrian Griffin will probably be back into the starting lineup (replacing Devin Harris), and will presumably start on Wade. But make no mistake, Wade will see plenty of Josh Howard and Marquis Daniels over the course of the series, along with whatever schemes Avery Johnson has up his sleeve. I have no doubt that Wade will get his, because he's just that good, but he'll be working for it.
And maybe the biggest question of all... do the Heat have any chance of containing Dirk? Looking at it, I'm not sure how. Looking at starting lineups, Udonis Haslem would seem to be the guy starting on him. I'll tell you now that Haslem has no chance at sticking with Dirk on drives to the basket. Same with a guy like Antoine Walker, who's not exactly known for his defensive prowess. Off the bench, maybe James Posey? I would think Dirk could use his postup at the FT line game all day long there. I just don't see how they can stop Dirk. They don't have the athletes on the perimeter. But then, most teams don't.
But the best matchup might be between the coaches. In each of the last two series, Avery Johnson has made huge adjustments (Devin Harris, Desagana Diop) which obviously have had huge impacts, and he has the roster to be flexible. Meanwhile, as TrueHoop says (he has the Heat in 6), Riley did something to bring this team together, and they're playing their best basketball at the most opportune time.
However, everything in this series for me points to the Mavs winning it. They have the best player on the court (right now, Dirk is beyond anyone else), they have the coaching, they have the depth at all the right positions (down low to guard Shaq, on the wing to guard against Wade), and they have the home-court advantage.
If Shaq plays like the did in Game 6 against Detroit all series, that's about the only way I think Miami can win. Well, that or Wade goes from great to Superman, and scores about 35-40 a game. But against the improved Mavs defense, I don't see it. These Mavericks are too fast, too deep, and playing too well right now.