It's also worth noting Murray exited the US open at the round of 16. Federer was a finalist and Djokovic the champion. So they're both defending a lot of points from that. I think it will be hard for Federer to get to the final again.
Exactly. While the Fed and Nadal can still cut it near the top they aren't, imo, what they used to be. The classic- big four was (for me) when Nadal and Fed were at their peak and Murray and Djoko were knocking heavily at the door.
Whilst it might still be them four in the top four currently, I can't really see either Fed or Nadal ever winning a slam event again (I hope Nadal does, but I can't see it). Really now it's the big one - Djokovic is clearly a class above all, with Murray a class above all - except that Djokovic chap - grr. Nadal and Fed are more or less also rans for me these days. I'm not sure why Federer bothers now but I guess he still enjoys it