Quoting from the gamethread since those die out after the game...
I think Hayward and Smarf are very good players who take undeserved flack. However, most of Tatum's leap has been from him improving in the PnR and working the stepback 3 into his game. It's him learning to be the primary engine of an offense. He'd actually probably look better if surrounded by players who played more to his strengths (he really benefits from Kemba's gravity), and less by playmaker types like Hayward and Smart.
This is a pretty interesting roster composition issue that the Celtics will have to deal with going forward, and they won't do it until they're really certain that Tatum is the real deal. But when they do decide that, there are a lot of optimizations you can make. Brown fits into this quite well (fortunately), since he can screen, shoot, play physical defense, and looks good when he gets the ball in advantage scenarios.