RealGM

Memphis trades + Dallas receives: Tony Allen, Hamed Haddadi
Dallas trades + Memphis receives: Vince Carter, Brandan Wright

Why for Memphis

1. Carter gives Memphis a big boost because he can still decently create his own shot and provides valuable outside shooting. Memphis will also have a team option to bring him back next season at 3 million (with an 800k buyout option)

2. Brandan Wright gives the team a cheap and capable backup center.

3. Presumably Memphis would lose Tony Allen in free agency anyway. Presumably the team's improved offense and depth would also improve them in the short term.

Why for Dallas:

1. Tony Allen provides valuable defensive help for Dallas, which can afford to deal Carter's outside shooting now that Dirk's returned. They get to evaluate Allen and see if they want him next season.

2. Dallas would've been forced to pick up Carter's option by the beginning of free agency. They'd probably cut him in hopes of landing a bigger name free agent. Now they wouldn't have to pay Carter's small buyout.

Surely Memphis values Allen more than Vince?

And while the value is good for Dallas we have a bigger need at SF since MArion only plays 30 mpg and spends 10 of that at PF. Allen and Mayo are too small to play together not to mention I dont think they would mesh well in the locker room in Dallas any better than they did in Memphis.

Value seems to favor Dallas slightly and the fit seems off for both teams.