Boston: Stephenson, Biyombo
Charlotte: Bradley, Bass
I think this is a pretty even trade talent-wise, and it would serve both teams well.
Stephenson is a ball-dominant guard that is struggling to coexist in a system with a ball-dominant point guard, because he needs to act as the primary ball-handler in the offense to live up to his potential. Bradley isn't ball-dominant by any means, and he's a good complement to Kemba. He provides similar, if not better, defense as Stephenson, and he's a better fit as Kemba's backcourt mate. Size might be an issue in the backcourt, but it didn't hurt our backcourt too much with Rondo and Bradley. Bass also would help Charlotte, because he's a solid defensive big to pair with the defensively inept Jefferson.
For us, Stephenson would work in a backcourt with Smart, because he's not really a ball-dominating point guard. Smart and Stephenson would be a terrorizing defensive backcourt, and there wouldn't be too much of a dropoff in shooting from Bradley to Stephenson. Now, there might be some legitimate character concerns with Stephenson, especially with Turner here, but if anyone can contain him it's Stevens. I also think Stephenson would benefit with Smart as a teammate, because he has someone who is just as fiery and aggressive as he is. If nothing else, if the potential doesn't show up by 2016, we can deny his player option for 2016-2017. This trade would also allow us to stay flexible with this season's goals. If we decide to try and make the playoffs, he will definitely help, but he's also young enough that if we sell off our veterans he'll still have his prime coming up in the future. So I think Stephenson is worth taking a chance on because of his great potential and his contract's third year team option that allows us to cut ties with him if he doesn't fit.
If we decide to go the tank way, a trade could also work out:
Boston: Stephenson, Vonleh or Biyombo
Charlotte: Green, Bass, Top-5 Protected 2015 Charlotte 1st rounder