If the current Celtics team could sign Demarus Cousins, and get his head straight, he would perfectly fill some huge holes in this current Celtic team. One of the few players that would kill two birds with one stone.
Number one... another offensive weapon that can find his own shot, and stretch the floor to stop teams from keying on IT. He and Horford both play well in the paint, and outside of the 3 points line, AND in between. This is huge, when teams have to defend you. The Celtics could still go small, with either on the floor.
Another is added team toughness, and a defensive force in the paint at the center position, to go along with AB, Smart, and Crowder.
The caveat is what do we have to give up to obtain him. If we're stripped clean by the Kings, it defeats the purpose.