She is correct in many points and I'll address that below, but here's one thing I am sick of: People claiming that just because there is something left that I haven't managed to do yet, the difficulty is fine.
The first time I got confronted with this particular issue was after the launch of Wrath of the Lich King. Naxxramas was very easy for almost anyone with raid experience, as was normal Sarth. Malygos was somewhat harder but not exactly hard compared to the older content that we were used to. That would all have been fine if there had been content for more experienced players as well. I didn't mind having an introductory raid instance, but it surely wasn't what I planned to run for months and months. Uhu, people said back then, but have you killed Sartharion with three drakes up yet? At some point I hadn't (later I did of course) but the point is stupid anyway. Yes there was a challenge in the game that I hadn't beaten yet, that doesn't mean that content in general wasn't too easy for me. I can spend only so many hours wiping on one boss before I get very bored - especially when I have already killed that boss countless times before (on a lower difficulty) and the rewards are low to non-existent. WotLK launch raid content was (for me) 20 jokes and a brick wall. Fighting and beating that wall was fun, but the way there was not.
If you take Larísa by her word and assume that the lower content wasn't meant for experienced raiders1 WotLK launched with a grand total of one boss for me. Yeehaw. For me, the countless raiders that are better than I am, and likely quite a few that are worse2, WotLK launch raid content was too easy.
Then came Ulduar, and things got a lot better. Not only did Ulduar provide somewhat challenging normal mode content (at least before all those nerfs) it also gave us a plethora3 of hard modes with respectable rewards to keep the better2 guilds interested. The pick-and-choose system for those hardmodes as well as the non-binary nature of some (i.e. Freya, Yogg-Saron - hard modes that you can scale depending on how much of a challenge you want) gave access to challenging content to a wide variety of guilds, and continues to do so even today. Ulduar wasn't too easy, it was just fine for most guilds I know of.
Ulduar mended my broken image of WoW raiding, even if I think it should have been launched together with Naxx and not months later. Naxx as the introduction to raiding and Ulduar for people who already knew what they were doing. But then along came Trial of the Crusader and it all went downhill.
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Now, you could say that this is just the elitists whining and that there needs to be content for normal players too - but I think that guilds at a lower progression level than mine are even worse off. Taking a look at the progression chart of my server we can find 44 guilds who have beaten Anub'arak in 25 men normal mode but only 6 who have killed any hard modes in the Coliseum. There might be some guilds, like Larísa's Adrenaline, who are on the verge of a hard mode beasts kill. Most of those 38 guilds, however, are stuck between farming easy content (Yes, easy. Only four guilds that have killed anything in there haven't killed Anub'arak yet. That is a sign of easy content.) and the brick wall that are the hard modes.
This can mean two things - either the hard modes are too hard or the normal modes are too easy, either way the gap is too big. Personally I can't advocate easier hard modes as that would make the whole instance trivial for my guild, something I wouldn't enjoy at all. With a diverse playerbase what you need is a diversity in difficulty and the hard modes seemed to be a step into that direction. Instead we get the one-size-fits-all super easy mode and the hardcore-only hard mode.
Before you tell me that normal mode coliseum is not that easy, let's have a look at those numbers again. Of the 44 guilds with Anub'arak kills on our server, only 18 have killed Yogg-Saron so far. By my interpretation this means that ToC is quite a bit easier than Ulduar normal modes, while dropping gear that is better than Ulduar hard modes. Difficulty-wise, TotC lies somewhere in between Naxx and Ulduar, when looking at the numbers. It may even be on par with Naxx if you consider the additional amount of time people had to clear Naxx.
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In short: A single challenging encounter doesn't make a tier hard enough, Naxx lacked a hardcore equivalent and TotC is way too easy even for casual raiders. Also, gear distribution killed Ulduar progress and was a very bad decision. Is WotLK too easy? That's a tough one to answer since Ulduar was good and TotGC is sufficiently hard. Are parts of it too easy? Definitely.
As an afterthought: Tobold says that WoW being too easy refers to the ease of getting gear these days. He summarizes this attitude as "What good is raiding if other people aren't jealous of you?" This is absolutely not what I am referring to above. While I do care whether gear is too accessible (as it makes my own gear less special, aka boring) my points are completely removed from the whole welfare epics discussion. What I care about is providing a challenge for a wide variety of players - and in that, the early and late WotLK content failed miserably. Do I like that the only difference between my gear and the gear of Joe Casual is a little green line that says "Heroic" on my tooltip? No. But that's not the point I'm trying to make here at all.
1 What she actually wrote was "Is there anything at all preventing you from skipping the faceroller raids altogether and stick to hardmode Ulduar and heroic ToC? Nothing. Nothing at all." I transferred that over to Naxx level content, even though the analogy doesn't quite fit, obviously.
2 I'm not trying to judge anyone here. "Better" and "worse" are purely seen from a progression point of view.
3 No, I don't mean a plethora.