My personal opinion is that allot of that has to do with his height. I think Levi plays better when he can see down the field, by getting him outside the pocket he can look down the field and see open players, when he is in the pocket he has a hard time seeing over the OL and DL and I think that is why he struggles to hit open receivers on slants. He is better outside the pocket and throwing into the flat and/or down the field. I truly believe if he were 6'1 + this would be less of a concern. He can get away with it a little more vs SBC and G5 opponents because they don't have the athletes that teams like Texas does. But even then he is much better on the move outside the pocket.