This is a good matchup for the Suns. It will play to Dallas's strengths, but those are Phoenix's strengths too. Brand devastated the Suns, but the Mavericks have no one like that. They have a lot of versatile athletes who can create a variety of problems, just like the Suns do. I certainly wouldn't give the Suns the edge "on paper," but I think it's close.
One thing to keep in mind is that, at least in my opinion, the Suns' second-best player (Marion) is better than the Mavericks' second-best player (Terry, I guess). If it comes down to stars making plays, and Nash can play Nowitzki to an approximate draw, "Good Marion" could be the difference.
I agree with the couple of posters who say that Diaw is key to the Suns' hopes. He has to play like he did against the Lakers. In that series, he became a pretty effective pick-and-roll partner with Nash; he was too crafty for any of the Laker bigs to stop. But he wasn't tough enough for the Clippers. If the Suns can get their tempo and keep Dampier and Diop off the floor (which I think is fairly likely), Diaw should be able to carve up the inside again. But he has to be aggressive and on top of his game mentally.
I think the wild card for Dallas is Stackhouse. Historically, he really isn't that good a shooter: 41% career, 40% this season, and only 30%/28% from three-point range. But he made a lot of big shots against the Spurs, at 44% overall and 41% from deep. If he can keep that going, the Suns' scrambling defense is likely to get burned. But if he reverts back to career levels of accuracy, the Suns' gambling is likely to pay off.
The Mavericks have only two major threats from the three-point line: Nowitzki and Terry. Howard shoots them well, but only very rarely (about one attempt per game); Van Horn shoots them adequately, but figures to play a Radmanovic-like role in this series -- in other words, a small one. Terry has to be honored and he will get his looks, but if Nowitzki makes himself a three-point shooter, the Mavericks have no inside game. That's a strategic victory for the Suns, because it eliminates an advantage that Dallas really should have.
I think the keys to the series are:
1. As always, the Suns need to dictate the tempo. Dallas will thrive in a grinding game where their centers can be a factor. Dallas can play well with a small lineup too, but at least the teams will be fairly level.
2. The Suns must keep their offense diversified and unpredictable. Last year, the game plan was to get Nash on Nowitzki in a pick-and-roll switch and let Nash torch him one-on-one. That won't be enough this time. Standing around kills this team.
3. The Suns have to be competitive on the boards. This was the same as against the Clippers: When the Suns rebounded, they won, and when they didn't, they got crushed. Pretty simple formula.
4. The Maverick role players are going to have to be efficient scorers. If Nowitzki scores 40 a game and Terry 30, that's not enough. If Stackhouse and Howard can do some damage slashing to the hoop and knocking down jump shots, the Suns will have their work cut out for them.
5. The Suns must make Nowitzki work on defense. Diaw and Marion should both be able to beat him one-on-one. With Thomas it's less clear.
6. Whoever takes better care of the ball will have a big edge. So far in the playoffs, the Suns have committed only 11.1 turnovers per game, which is excellent (especially considering the overtimes!), but the Mavericks aren't much farther behind with only 12.4. The Suns have a better turnover differential than Dallas, 3.5 to 1.9.
7. Most games will be close. Both the Suns and Mavericks have a tendency to cough up big leads. Crisp execution and the avoidance of mental errors down the stretch will probably be the biggest factors of all.