I simply don't understand the Exum hate. It doesn't make sense. The kid had two bad injuries yet he gets out there and plays with all heart. Sure, he is extremely rough around the edges, but he's still young. If a guy like Andre Roberson can be so abysmal on offense but be good enough defensively that his absence caused a huge void for a contender, then I think Snyder is smart enough to harness all the good that Exum can become.
There are times he simply blows by his defender. And there are other times he simply shuts down his offensive counterpart. Yes, he has to get better and more consistent. If both he and Royce can make improvements, we would have the best defending perimeter in the NBA with Mitchell, Exum, Royce and Crowder.
Stay positive and have faith.