I'm still not convinced he has a complete game. We will see, he certainly has time
The "time thing" is over played. Even in this era where you win a bit later, it almost always clear when they are young who the future champions are. We have seen that in Fed, Nadal, Nole even Murray. If your not seeing the results by 20, your probably not going to at the very top levels.
The question asked around here a lot, which is a valid one is who's next. We haven't seen him yet. But that can change quickly so i'm not to worried.