Sorry I just don't believe the Celtics will excel with IT as the starting point guard. I don't care who, (within reason) you pair him with. If you pared him with Cousins, he still wouldn't defer to him. (Been there, done that, the Kings traded him.) We on the other hand are dying to give the pairing another go.
He's a defensive liability, he dominates the ball to score as much as he can. He thinks the more he scores, the better the chances are of a Celtic victory, and that's the way he plays the game, he still showing the NBA what a mistake they made about him at the draft years ago.
Sometimes it just seems to me he would rather challenge at the rim with acrobatic shots, than pass to an open shooter 10-12 feet away.
In a winning scheme, IT would come off the bench, replacing a solid Celtic PG, at opportunistic times during the game. And be very valuable to the team as a 6th man.
If I'm wrong, and I hope I am, I'll say it.