There's a common misconception that MMO's in general are getting easier. But 'easier' is a term thrown around to describe a multitude of things. For example, its said WotLK was easier then Vanilla WoW.
The hardest part of Molten Core was getting 25 people (yes I know it was a 40 man instance, this is my point), to come along and stay awake. There was no concept of a DPS rotation, it was there, but no tank could hold that threat, they weren't designed for it back then. Rogues backstabbed, Mages frostbolted, Hunters auto attacked, Warlocks shadowbolted, a class that could heal healed, and Warriors tanked. And that was it.
Back then a friend of mine and myself played hunters and during a raid we'd autoattack and then play Soulcaliber or Smash Bros.
To say everyone is running around in purples is true, it is easier to get purples, but its just an item color. This would NOT be an argument if all gear had white text. Yeah you can get into ICC by doing 5 mans. So what? Doesn't mean you're gonna clear the place. You still gotta grind out the heroics for tokens. How is that different then putting old school raids on farm? Oh you don't need 40 people to do it now.
That doesn't make it easier. Unless you think Autoattacking, Frostbolting, and Backstabbing a boss with 26 DPS is hard. Or is it getting 40 together that is the hard part?
Now that we can argue about. What makes the challenge? The encounter, or the organization before it? Well here's my opinion. World of Warcraft while based on Warcraft is not a RTS. You want organizational challenge, play Warcraft. The encounter should be the hard part. That is the direction WoW, EQ2, and others are heading.
And it shouldn't be an annoying 'hard' either. Requiring a raidwide cure curse 6 times a minute with the spell being on a minute cooldown and the curse instagibs whomever its on if not cured in 4 seconds isn't hard. Its annoying (looking at EQ2 here).
Tactical position and DPS/Tank Rotation and Healing Priorities is where the challenges should be. Not being "Hey.. do we have 8 healers on tonight?" If you ask me, Tank/Healer/DPS should go to the wayside and be replaced by DPS/Support with each class being able to do either depending on spec. Put more focus on tactics in that case.
But WoW hasn't gotten easier. Blizzard just doesn't know how to color the text on the equipment. If they made Pre-Naxx gear White, Naxx gear Green, Ulduar gear Blue, and Crusader Coliseum gear Purple with all the same stats and item level, you wouldn't see people bitching that gear is easy to get. For example:
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Became like this:

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Same stats, but the bitching about items being too easy to get would cease. I would dare people would bitch that its too hard to get purples.