As someone who is both a Mavs (for the last decade) and Suns fans (Suns are #1 in a close race right now for my favorite team), I probably have the best perspective/analysis of Wright's game on this board (unless there's any other dual Mavs/Suns fans).
I LOVE this trade for the Suns ... Assuming the guards involve him in the offense.
He is an ELITE finisher / pick and roll player - His touch within 10 feet of the basket seriously may be the best in the NBA - Not just dunks, but even floaters and those types of shots. As long as he's not touched too much and/or not hit/fouled, he'll hit shots in the paint with literally the highest efficiency in the NBA. He's not much of a 1 on 1 or post player - He can shoot a bit out to 15 feet, but it's not something you really want him to do.
He's not a physical player and this is his big weakness. His rebounding is mediocre because when there's a lot of physical contact, he just can't handle it. He's so long he gets some rebounds, but he's not a "battler". So in terms of rebounding, he won't help really. (assuming he plays at Center).
Although he can get bullied inside defensively, he isn't that bad on that end. He's such a good/quick athlete that his P&R defense is pretty good. He also plays smart - doesn't make too many dumb mistakes. His length / shot-blocking make him a surprisingly pretty good rim protector. He's been used at center the last couple years in Dallas and was often used (before Chandler got here) to close out games at center in Dallas' small lineup ... Because of his above-average rim protection. His blocks per minute this year is actually similar to Len's at 1.3 in 17 mpg.
Again - Assuming the guards aren't selfish and involve him in the offense, he's a HUGE asset on that end. W/ the skills/ talent in the Suns backcourt, they'll be near impossible to stop in P&R's/penetration w/ Wright ....