Same reasoning holds, I think. I like the fact that we have an era with four top players competing at the same time. 2012 saw them pick up one Grand Slam title each, with Murray winning at the Olympics and Djokovic at the Tour finals, so a very even contest between the four. 2013 saw Nadal dominate and Federer seeming to fade out of the picture. So that he is back in it, and still competing (albeit so far only against Murray) suggests that the era of the Big Four (rather than just a big three) might have another year in it yet!