So Jeff over at MMO Weekly wrote a pair of articles outlining the self-destructive pattern that WoW is falling into. His critique, however, is two expansions too late. The problems he's talking about were strongest in Original WoW, reduced in BC, and are even further eroded in WotLK. In reality, I think the destruction now is coming NOT from making the endgame 'too exclusive', but by making everything before the raid endgame too easy.
I loved The Burning Crusade's 5 and 10 man dungeons. I loved the Heroics, even though they didn't offer upgraded gear at that time, only badges. Both heroic and regular 5 mans required teamwork and strategy, and people had to learn the fights and utilize crowd control effectively. Even though they were 'only 5 mans', they were fun, and Heroics required some work to succeed in. And since 5-man dungeons are my favorite part of the game, I was happy. I could log in, run a heroic or two, and have fun.
Then WotLK came out. The instances were now super short, easy, with tiny loot tables that ensured you got everything you wanted in perhaps 3 or 4 runs, tops. Crowd control was basically rendered useless (my Mage and my trap-savvy Hunter wept), as now every tank could 'aoe tank', and most groups just rained aoe on group pulls without any need to think. Trash mobs were just that -- trash, with nothing needed to learn or beware of. Just shoot 'em til they were dead, and move on. Heroic dungeons are virtually indistinguishable from their Normal mode, aside from the upgraded drops and badges.
WoW's problem is not that 'reaching endgame raids are too hard'. Their fatal mistake (in my opinion) is that Blizzard tried to make endgame more 'accessible' by completely trivializing all aspects of the game that lead up to it. Therefore the entire game experience is now watered down and rendered pointless, since Blizzard has basically admitted that it's all just a speedbump, and not content that has any intrinsic value, or that should be enjoyed on it's own merit.
And THAT is what destroyed most of my interest in WoW. I was never a hardcore raider, nor was I a pure 'casual' player. For someone like me, WotLK's 'easy mode' style of play is a waste of time for me. I've been reduced to running once a week 25-man raids with my guild as an excuse to even log in anymore. Since the game has nothing in it that isn't built directly around the watered down 'speedbump/treadmill' that is now meant to feed playerfodder into the 'endgame', it's just plain boring. This is why immersive worldbuilding, RP tools, robust crafting mechanics and community is something so important in an MMO. Because without any of those things, I'm quickly losing any interest in continuing to play the game... since there is basically nothing in it for me anymore.
Gear drops do not provide a tie to the game world, or anything lasting (since gear is invalidated so fast and even if you like the look of it, you're 'not allowed' to equip your character according to aesthetics). If it wasn't for my guild, which is made up of great people and holds a lot of happy memories for me across the 5 years that I've been a member of it, I would've quit months ago.