I know what you mean but for once we have real good reasons to expect a player to be a true star. Why not start to enjoy it now?
Its tough to say with average league scoring changing frequently due to rule changes. If league scoring ever goes back to something like 05-06 levels during Gally's prime a 100pts season might even happen. Under current scoring rates I think 70-80 is realistic.
He's such a complete player, not in the sense that he's good/average at everything but rather that he's great/amazing at everything. As you say first step could be better but he's still a 18yr old prospect, he probably knows it and with that mentality he has he'll come back after next summer as the quickest and best skaters at camp