He was exactly ten and five, so he is obviously not out of his mind. Now that he'll get the ball passed to him, I think that the points will go up.
But what did he replace? Devin Harris relied almost entirely on his quickness on the dribble to get his points. He didn't have crafty moves, he relied on speed, and his speed is going down as he ages. Oh by the way, he couldn't do a consistent pick and roll to save his life, and the Jazz system relies heavily on the pick and roll. Now I'm not sure if Mo can do the pick and roll, but he has to be better than Devin was, and he can shoot. and he's tougher physically and mentally. All he lacks that Devin has is maybe the speed, but guess what, we have wing players with speed now, so no big deal.