I just feel like his (Djokovic's) movement is very well adapted/adaptable to clay. Federer first won Wimbledon and then also the hardcourt slams, and it just feels like his success in the FO is more a result of hard work and talent in other respects than an innate feel for the surface.
How many sets has roger lost on the way to the final since 2004?
I don't know and I don't care. I just gave an opinion, which may be ill informed, but I'm not going to waste time thinking about sets lost and such. Roger simply hasn't produced the same level of success at RG as at the other slams. This is something undeniable. He's reached many semifinals/finals in the other three slams and won many of them, whereas he's only gotten to two RG finals and lost both (and it wasn't even close).
Now, I'm not going to compare Novak to Roger at the moment, as the difference between their accomplishments thus far is vast, but I would just point out that Novak has reached semis already at all 4 tournaments, 2 finals, and won one of the finals. He will always remain best at hardcourt - I am sure of that - but the fact that he already reached at age 20 both the FO and Wimbledon semis (and fell to Nadal in FO and was worn out/injured at Wimbledon when he retired) suggests that he is perhaps more innately versatile across the surfaces than Roger.