As we've discussed on other threads, I don't get too worked up over what is peak and what is prime, and all three of The Big 3 have helped to redefine what prime and peak is. Somewhat.
2011 Novak may have been his most electric period, when he ascended to the throne in dominant fashion. The tennis world wasn't (yet) used to him taking it to Roger and Rafa like that. His baseline game was more aggressive than in 2015-16 - which may have been the best year of play that I've seen, with Fed and Johnny Mac, and Rafa all in the running.
His best results were in 2015-16, and of course, if we extend the timeline through FO16, we get the only 4-in-a-row since 1969. This may have been Novak's best 12-16 month stretch which can match or exceed anyone's. He had the same speed as in 2011, and while not quite as aggressive, he seemed to be smarter tactically.
Today, we only really see "that guy" in briefer stretches, and both of his Wim18 and AO19 wins over Rafa could hang with his best from '11 or '15-16. Is this because he's trying to peak for majors, and saving something for those runs, or because he can't keep up that high level for a full season?