I am lazy to find the stats but I am pretty sure that there were more winners and net points in the matches between Fed-Djoko (final) and Fed-Murray (semi) in Cincinnati. Why can't the same quality players, world no.1 and 2 prevent winners happening when they play against Federer but they are able to do so when they play each other? Even in each set of USO final which Fed lost, he made tons of winners and net plays against the very same World No.1. If you're saying he was the winner after all, that doesn't relate to this discussion.
I think in general Fed has always gambled more returning. He does not win as high a percentage of his return games as Murray, Novak, Ferrer, some others.
http://www.atpworldtour.com/en/stats/return-games-won/all/all/all/
Look where Fed is.
Now for HCs:
http://www.atpworldtour.com/en/stats/return-games-won/all/hard/all/
Same thing, way down the list.
Look at the four at the top: Murray, Agassi, Novak, Chang.
Sampras is back at 93
Notice how high up on the list old Connors is.
The key to the game of Fed and Sampras is high risk at key moments returning, then hold serve.
http://www.atpworldtour.com/en/stats/service-games-won/all/hard/all/
Suddenly Pete and Roger are only under servebots, and a bit under Roddick.
Roger's game is built around quick strike tennis, as much as we can have that in 2015. He gets so many winners serving because his serve is so good, setting up easy one-two combinations.
Novak and Murray can't do that. Their serves are not good enough. Novak backs his serve (which is good) on HCs about the way Nadal does on clay.
Take a look where Murray is on this list. His serve is HORRIBLE compared to other great players.
Novak winning 86% of his service games on HCs for his career is impressive, but again he backs up that serve with defensive skills, as Nadal does (or DID) on clay.
Even this year, probably his best ever, he is down a full 5% below Roger.
If Novak had Fed's serve he'd probably have about 20 slams already!