I agree with the general premise that if Stubbs can bat like a league average CF (or even slightly below average), he's going to be a very valuable player.
Is he going to be able to do that? I'm a little skeptical, but hopeful. IMO, this is the type of young player you want to take a chance on. His defense is good enough that if he struggles with the bat, he's not going to drag down the entire team. That was one of my huge problems with Larson getting so much playing time. His glove was so horrible that when he failed to hit, he was contributing absolutley nothing. At least Stubs will contribute on defense, even if he struggles adjusting to ML pitching on offense.