So, does that mean there is just enough?
Problem is, WoW works for everyone, from casuals to the hardcore, whether it be PvE or PvP. But they will never please everyone all the time.
Some wanted the 5 man instances to much harder than they were before. They were, then the casuals complained they were too hard. Blizzard starts to nerf them, then the hardcores complain they were being made too easy.
Raids, kind of the same thing. Except this time, a lot of the more casual raiders were so used to the last 6-8 months of WoTLK where it was literally a faceroll to clear ICC due to the encounter nerfs and zone buffs. So many people were being carried through that didn't have to learn the mechanics because they were just healed through their mistakes.
The raids in Cata (at launch) were very tough, some more-so than others. ie: Al'Akir was bloody ridiculous RNG fight that wasn't fun at all, even if you knew the fight well.
I personally stopped playing because of a few things, but one of them was that I was tired of having to rely on 9+ other people to pull their shit together and be prepared for raids.
In the end, as much as I enjoy WoW (at times) I would rather spend 4 hours actually playing a game and not waiting on people to start a raid, and then having to teach them boss mechanics in detail because they didn't bother to watch vids and read up on the fight on their own time. Then watching them fail miserably on those mechanics for 2 hrs and waste my time.
A small core group (10 man) of us got the first 4 or 5 bosses dead before the end of December (launch was early December), and then the guild started 25 man raids and they couldn't even get those first 4 bosses dead in 6 weeks of raids, even though half the raid could do it 10man easily. The other half of the raid were trying to raid in quest greens, ilvl gear that wouldnt even get them into 5man heroics, no buff food, no potions etc. The guild leader let this happen, guild splintered because of it, and I stopped logging on.