It's not over yet - though now it's more Fedalovic/Big 4 rather than just Fedal as it was in the past - but clearly this season & possibly next might be the last. I wouldn't be totally surprised if Fed hangs up his racquets this year if he gets his fairytale ending - slam and/or Olympics... Can't see him going beyond 2013. As for Nadal I also think 2013/2014 might be the end if he thinks he won't win slams anymore. So either way we're certainly getting towards the end.
What I don't understand is why people are so keen for it to end or act as if it was the worst thing that ever happened to tennis.
I think once those 2 guys are gone people will realise how important they were to tennis and just what they brought to the game. When we have Raonic vs Tomic finals (or more likely some other transitional players who ala Baghdatis or Gonzo have one good run...) we'll look back at WTF 10; Wimby 08; Wimby 07; Rome 06; Miami 05 etc. as a golden era when you had 2 of the best of all time slugging it out & showing some outrageous tennis. The same is true for Djokovic/Nadal too - sure it was one sided last year but overall they've had great matches - the level of tennis in both Madrid 09 & US Open 10 & 11 was insane at times. Enjoy it while it lasts. Tennis needs big personalities - people here seem to want it to be like the WTA is now - a new no.1 all the time, top players losing early in slams all the time, no big names bringing the game to the masses.
Even the most anti-Fedal posters will be all nostalgic at Wimby 2018 when they have Fedal in the Royal Box watching the final a decade on from their classic.