Originally Posted by ellipticality_224
Its a matter of your style of play. Take Fed for example, a very laid back style of play, not hard on his body, as well as him being good, therefor, reigns for quite some time, Nadal on the other hand, very hard on his body, better than Fed most of the time, but must rest a lot, and very injury prone, however, both these men are deserving of a no. 1 ranking as well as Djoko and Murray. All four great players and deserve the No.1 ranking more than the last. And there are women like this too.
Now we are getting into the surface debate again. Federer came into tennis when tennis was being gradually shifted to slower courts. As you know, faster courts = less chance of injury.
Notice how the finals of the AO 2013 were influenced by the injury of the one player. The AO's surface is far more brutal on the body than before.