I've already agreed with the consensus here, so let me now defend the OP just a little.
While I don't think Stevens is going to hand the keys to Tatum, I do anticipate him running more of the offense as a pick and roll ballhandler next season. I think he's shown that, if he continues to work, he'll be 100% capable of that and we'll see more of it next season.
This is part of what makes me so excited for the potential of next year's team. Jaylen has also made strides as a ballhandler. If he and Tatum keep it up, the C's could have 5 guys in the starting lineup who can run a pick and roll from either side. That's crazy.