That's my logic on Wall (much like Monta Ellis). He's (to me) an undersized 2-guard. He flourished in Kentucky's system and was great at leading the break (because he could basically leave everyone in the dust). But, he won't have that same success in the NBA; not at first, at least. He's going to have to develop his half court point guard game and his shot.
But, I could be wrong. I watched a lot of Steph Curry during his senior year at Davidson, and didn't think he could be an NBA point guard. I thought he would be basically an undersized 2. But, he definitely proved me wrong in Golden State this past year. He could run the break in Golden State's hurry up system, but when they got slowed down into the half court game, he showed that he was a very impressive director of the offense and was great at setting up his teammates.