It's not going to bother me if he gets sent down, although I think whatever he needs to learn is better worked through at the ML level. If he goes back down he's just going to have to pick up his learning curve against ML pitchers when he comes back up. I would give him at least 100-150 at bats before possibly sending him back, though.
As far as the timing of his being called up, I remember what Buck said when asked if Manny was maybe called up too soon and wasn't ready, he said "you can't ruin the great ones", which I for the most part agree with.