Yeah some specs and classes go through the ups and downs, but consistently Ret is crap in end game. Time and time again they're only brought for niche purposes and thats about it. The last expac where ret could be at the top with the rest of the dps without some stupid glitch or exploit is the end of WTLK, and even then the usual classes out ranked them.
People then like to bring up that ret isn't top dps because its a hybrid class, yet druids the hybrid close to them does consistently well in dps in almost every expac.
After what happen with Ret and Gurthtalak in Dragon Soul I've given up ever having faith that blizz even likes ret, the same patch that had arms wars and many other melee have extra procs from mastery and their basic mechanics. Yet the seal that was part of our basic mechanics and was basic filler somehow was to op with it.
To stay with this topic though, its the same as many here I've played it for a long time and have the most accomplished on it.