Djokovic simply was too exhausted mentally and physically. He wasn't usual himself and his legs simply didn't move especially in first set. Vajda his trainer was also absent.
This form was good enough for him to beat all others except peak Federer. He will come stronger from this defeat as usual.
For me peak Nole is better than peak Federer. Federer has better serve and voleys but Nole has better return of serve and is stronger from baseline. In Cincinnati finals we simply looked match between 100% ready Fed against 50% ready Nole and to beat Federer that simply is not enough.
Whilst I respect your opinion. This was Federer's first tournament on Hard, compared to Novaks having won Toronto. Novak has had better preparation.
This isn't peak Federer. I know Novak fans would love to say it is. But Federer was simply awesome in 2005-2007. He really didn't lose any baseline rallies, or miss many first serves in those days. Federer played like that in the first set. He used to play like that in every game, of every match, in every tournament.
Novak is still the favourite for USO.