On a different note, win% isn't everything but it does tell us something. Here is now Fedalovic rank in career (Open Era) win% on different court times:
HARD
1. Djokovic 84.25%
2. Laver 84.14%
3. Federer 83.49%
....
12. Nadal 76.97%
CLAY
1. Rafa 91.75%
2. Borg 86.02%
3. Lendl 81.03%
4. Djokovic 80.08%
...
15. Federer 75.89%
GRASS
1. Federer 87.23%
...
9. Djokovic 81.91%
...
15. Nadal 77.22%
Or to put it another way...ranks on hard, clay, grass:
Novak: 1, 4, 9
Rafa: 12, 1, 15
Roger: 3, 15, 1
Novak is the most balanced, Rafa the least. All three have the greatest win% all-time on one of the big three surfaces, with Rafa having the largest lead by a good margin. The gap between Novak and Roger on hards is tiny.
No clear conclusions to make, just food for thought.