I contend that LFR and easy mode raids is what has led to the downfall of WoW. In the developer's selfish response to the percent of players seeing end-game content being too small, they felt as if their time was being wasted, or could be better spent if they didn't make content only a few would see.
So they removed the center of the donut model. Everyone can now essentially see all of the content with really little time or effort. You now have nothing left to work towards content-wise except for altered mechanics (at best) or inflated gear stats (which is only good for attempting harder modes). This doesn't get the 'casual' audience climbing upward, but it DOES deflate the sense of risk/reward for the hardcore audience.
Back when I was raiding (THE GOOD OLD DAYS, hear me out), I knew that there was a bunch of content I might never see - but that kept me playing because there was always content left to see. If they gave me an easy out I would have completed it and weighed the time investment involved in gearing up to attempt "Hard Illidan" and just... not done it.
The donut model is very important. If the WoW developers feel let down that there is content that some might not get to,
make it relevant later. Put in a bunch of stuff people can go back and do, design them to still be challenging coming back and doing them post-expansion with a gear/level sync system, and/or add in aesthetic rewards that don't disappear on a timed basis.
Instead, they made hard content, didn't feel like people weren't seeing it, and then cried about that and then turned around and made the content worthless a few months later anyway. Dumb.
I think Blizz got tired of designing raids like Naxx and Sunwell that about 1% of the player population (maybe less) would ever see at their time of release.
Can't blame them.
I do blame them for this short-sighted and vain outlook on the great model they destroyed.