Guga, Costa, Corretja, Bruguera, Muster, Courier, Ferrero in 03, all better than Fed on clay.
None of them made three finals in a row, or 4 semis in a row. Why is that? If they were such good claycourters, why were they all so inconsistant?
I'll give you Guga, Bruguera, and Courier, but the rest aren't better then Federer.
Let me put it this way. Nadal is 28-0 on clay. He has never lost his entire career there. Next year he will break Borg's record of 32-0 at RG.
He has a serious claim now to be the best claycourter of all time. He already broke Borg's streaks on clay with 81 straight.
Now Federer? He's only ever lost to Nadal at the FO in 4 years.