For the record:
1. Lou Williams isn't who he used to be and it's questionable whether he'll ever be the player he was in 2012 ever again. ACL tears can be a bitch that way.
2. Bebe has knee problems, and for a center knee problems are one of the three things you don't want to hear about (foot and back are the other two). There is some question if he can ever be a starting center because of those knee issues. That's why Atlanta was willing to deal him.
3. That said, it's still a good trade for Toronto, because if one of Williams or Bebe finds his form or overcomes their nagging injury issues, we basically got an additional asset for nothing (since we were going to waive Salmons regardless). It's just not the mega-steal people are making it out to be.
4. Finally, trading Bebe for Ennis would be the definition of a no-brainer. Bebe was a mid-round big man pick in a bad year; Ennis was lottery-level talent in a good year. If that trade becomes available, you make it and you don't think twice.