There is nothing wrong with May's shooting, he just has the ball handling skills of a toddler.
May could be a key piece if he learns that dribbling is important and does all he can do to make his dribbling skills better.
May has tried to model his game on Gatens and done a good job of it- he's academic all BT after all. However, he doesn't have Gatens' skill set- as you were saying ST, no dribbling. He is probably the worst ball-handler we have in the guard court. I think he can learn from Hubbard, who is about the same size, about an inside-out game that could make May consistent offensively. If May can develop a step into the lane area and rise jump shot in traffic, he becomes a different player. Until then, he 'might' just see spot duty.