Yeah. If it's pruely a size issue, I am closer to accepting it. And maybe that's all this is. But there are ways to work small players capable of explosive plays into the offense, especially when a major concern of the offense is its lack of explosive playmakers. Ajay Allen was 5-11, 185.
I hope he fills out and developes like you say. I just know running backs who have to redshirt are few and far between and do not have a good track record of success.