Mobility wise, Davis had a long way to go to play the 5 in college. I'm sure he'll have made improvements, but if you can't play the four in high school then you can't play the five, at Michigan, in college. The four is a perimeter spot.
We never quite got to the point where Michigan would play a guy like Mitch McGary at the four consistently and he could move, handle the ball and do all sorts of ridiculous things for a guy his size.
If Austin Davis is playing the four at any point next year, something went off the rails. Maybe you could see a Wagner, Davis lineup with Wagner at the four, but I still strongly feel that takes away from Moe's strengths and would have to mean that Davis is a better option than one of the many guard/wing options that U-M could insert into the lineup.
Building off this, Michigan used to be unique in the sense that it had a small ball four, but look at the Big Ten next year and Minnesota is almost the only team who will play a post-type player at the four. These are some of the names that Michigan's 'power forward' will probably be guarding... Basically a bunch of versatile 6-7 guys:
Vince Edwards, Juwan Morgan, Justin Jackson, Jae'Sean Tate, Miles Bridges, Ahmad Wagner, Sanjay Lumpkin, Leron Black, Isaiah Roby, Lamar Stevens...
I can't imagine Austin Davis (and really Moe Wagner) guarding them very often.