Yes, it's not a coincidence. LFR was added to slow the exodus that long predated its introduction. People have been shit upon by the exclusionary end game, and have been quitting over it, since Vanilla. Of course, for a long time the influx of new players masked these losses, but the devs knew the game was bleeding even back then -- that's why they kept changing it.
It's perennial hardcore bullshit that people like playing a game that treats them like dirt. No, if a player discovers the game activities one is supposed to be doing aren't designed for them, they quit.
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Durumu was heavily nerfed. After the nerfs, you could pretty much ignore the maze. Even so, lots of people still got run over by the beam.
And then there's the epic nerf train they applied to Nazgrim.
What LFR could use, I think, is something that tailors individual reward to performance. Also, a mechanism for identifying some kinds of trolling and booting the trolls would be useful.