1) Federer has 69% of his titles won on HCs while Djokovic has 76%
2) 2/3 of Djokovic's slam titles are also on HCs. Federer and Djokovic has only 1 slam on clay (both avoided RAFA en route)
3) Federer has won 77% of his masters on HC and Djokovic has win 73% of masters on the same surface.
4) WTH are you talking about? RAFA has won multiple Wimbledon and USO titles. Among masters he has won IW, Canada multiple times as well. So your failure of retaining titles is a lie.
5) Federer's H2H on clay 2-13 and Djokovic's 7-15 against RAFA
1- The ATP Tour is composed of 67 tournaments, 37 on hardcourts, 22 on claycourts and 8 on grass, which corresponds to 55% on HC, 33% on clay and 12% on grass, this shows you that Rafa's figures are far too unbalanced compared to his competitors.
2 and 3 - Again, when you look at the surface distribution in Grand Slams (2/4) and Masters 1000 (6/9), it's normal for versatile players like Federer and Djokovic to win more on hard than on clay, unlike Nadal.
4- By failing to retain a title, I mean being unable to win a non-clay tournament two consecutive years at the very least.
5- Nadal is the best ever on clay, that's the only place where he dominates his opponents as I said.