Did they enforce the rules ? I don't put the sound when I watch matches on TV because I don't want to hear the commentators' gossiping but I didn't see any player reacting to a warning in any match
And believe me, Monfils sometimes was quite slow
As for Djokovic, I didn't have the impression that he tends to miss because of "overthinking".
I think he's always dealt very well about concentration on big points.