Yeah, that's basically what I'm trying to say. Plane, movement, deception, etc really are part of "stuff". He either has it or he doesn't, and all signs point to him having it. The only real worry imo regarding his height is durability. So far it doesn't appear to be an issue, and even if it does later on in life he can move to the pen when it occurs.
Even guys like Tom Gordon who did eventually move to the pen put up good seasons as a starter first (and Gordon didn't have Stroman's command).