TT seems like a good guy, suggesting you could get much more out of him seems pretty unlikely. How do you use him more effectively? Put him underneath? He struggled to rebound and to stop people when they challenged him at the hoop, he has no big man moves to speak of, and mostly, he floated on the perimeter, where he is not skilled as a ball handler or passer, and as previously mentioned, shot 3 for 25 from three, with some really bad misses that weren't close.
So is that Johnson's fault? I had some issues with Johnson's decisions this year, but I still think he can do something as a coach, and when TT didn't box out on rebounds again and again, he finally got benched. In this case, that's what a coach should be doing.