The Dimitrov-Federer match was interesting imo. It really told us something about Grigor.
At the end of the day, both these players have some similarities in their game. Now, Grigor clearly moves better at this point of his career and looks a lot like Federer did in his prime, what with the great running forehand and gets. However the indoors venue neutralized a bit of that advantage, and allowed Federer to make up for his somewhat less good footwork, and really emphasized the actual ball striking and timing.
And there you can really spot differences. I thought Federer won most of the bh to bh exchanges. His bh had a little more bite and topspin to it, and really pushed Dimitrov backward. Federers forehand is both more dynamic, and can create angles that Dimitrov's cannot. Finally, Federer would actively take the center of the court and hit balls a little earlier than Grigor. Then of course the dynamic at net was also a big win for Federer.
At the end of the day, Roger just has more options available to him at almost every spot on the court, and it showed us that Grigor, while talented, doesn't quite have that one 'killer' counter that he can go too when an opponent deals with his variety. He doesn't have a Djokovic backhand, or a Rafa cc forehand or a Raonic serve.
Imo that's why he won't be as big of a champion, assuming that he does break through in the next few years.