Fed was better in 2015. That's not even a dicussion. Especially from Wimledon to the USO. Murray was losing to Djokovic and Federer but that's pretty much it. While in 2014 he couldn't beat a lot of players.
Wawrinka was the same in both years. If anything he was slightly better at RG 15 than...
Djokovic played well at Wimbledon 2014 but you can't deny the mental demons he had in that match.
As for USO 14, he got married right after Wimby 14 which is why he wasn't in the best shape right up until Beijing 14.
The same person who almost choked it away from 2-1 5-2 up.
That was the match that changed Djokovic's career and made Djokovic 2015-16. Also the current Djokovic who isn't as good but might be even more mentally strong.
Had Djokovic lost that match he would be at Borg's tally at best and...
According to ATP stats from 2019 here are the top 5 servers on clay.
2. Sam Querrey
Are we saying that Nadal has a better serve than Kyrgios or Opelka?
Nadal's serve/return combo isn't what makes him special on clay
Yes but two surfaces are more than one. Plus Nadal is almost impossible to hit through on a clay court which is why he has such high stats. I bet you anything he is harder to break than Fed on a clay court. Does that make him a better server than Fed? It has little to do with his serve or...