Fed isnt going anywhere soon.. pretty soon if you google "what can survive the Apocalypse", it will be the cockroach and the tennis game of Roger Federer.
I think Rafa's game has been architected to beat Roger's game but Roger's game has been built to outlast this current generation of ATP pros. Yes there seems to be a decline in Roger's game at times over the past 3 to 4 years but not really. Just as he did in 2012, Roger is most likely win Wimbledon again this year or there after. I understand why his fans admire his game because its really special to watch and it looks so effortless on his part. Most Rafa fans really like Roger but really felt a change was needed because the game of tennis had become predictable during the time of (2003-2007). If you think about it, there were maybe 2 or 3 great matches during that time (for me I can only think of AO 2005 ( Safin def. Federer: 5-7, 6-4, 5-7, 7-6 (8-6), 9-7). The past 7-8 years has produced the rise of Nadal, Djoker and Murray. Their baselines games combined with Roger's has made this current game of tennis the BEST ever by Far.
Fed winning #18 is not good for the current game because it really means that his record of (men)GS titles will Never get tied or broken in our lifetime. It means that Murray has no chance at the age of 27 and Djoker will have to go Federer type of run for about the next 5 years to even get considered which is highly unlikey. Four or five years ago it was safe to say that Nadal was the 2nd best grasscourt player on the ATP tour but now Rafa's grass court game is in such a huge decline, that it may take Divine Intervention for him to even make the Wimbledon semi yet alone the finals. That means to catch or tie Fed, Rafa would have to win aleast 2 more US opens , another title chase at the AO which again is gonna take Divine Intervention because he has gotten injured atleast 4-5 times at that tournament and a few more RG titles which is obviously his best chance. Records are made to be broken, that is the fun of Sport but when titles are beyond belief or human effort, there is no thrill or real challenge in the game(sport).