Mitchell's biggest issue is his efficiency and shot selection, but he'll work through it and being the savant he is, he'll learn from the experience and improve. He's done that his whole life so no reason to think he won't do just that. That's what going to make Mitchell deadly is his ability to learn. He's already accomplished a ton, but there's still more he can do.
Utah needs another scorer who can create their own shot but work within the system on both ends of the floor to ease up on Spida's workload. I'm sure SL and Quin have some ideas that won't destroy the chemistry this team has and without giving up any key players. Just a matter of doing it.