Hard, and not pugged while current.
So, hard.
So, not done while current.
You're one of the very few claiming Anub'arak was easy.
So, hard.
Look, I'm not trying to say "you found this content hard"; that'd be unbelievably arrogant of me, and it's not where I want to go. Only you know how hard you found something. That said, your experience doesn't account for everyone's, not even within your own raid group; the difference in role difficulty alone makes this a given. I don't know what you did back then, but if you were a Protection paladin you had close to the easiest job in a raid.
What I'm saying is that those who say WotLK was easy, 99% of the time, didn't do any of the hardest content - they avoided it. As an expansion, it was as difficult as it ever needed to be because we didn't see hardcore players leave the game because it was too easy.
Further to that, I'd also argue that raiding activity among the top guilds was far healthier then, rather than the ludicrous levels its gotten to now (when some guild masters promote the use of narcotics).
World of Warcraft doesn't need to have the content as hard as it does now. It really doesn't. WotLK was the perfect setting, IMHO, because it catered to pretty much everyone without omission or patronisation, and built server PuG communities that didn't require an ugly queuing system. It also encouraged casual raiding which got people on the way up to better guilds, a tap that has literally been turned off since Cataclysm and guilds are now eating each other as a result.
That's why WotLK commonly comes out on top in most polls.