... happened over two years ago, at level 60, but at that time we only killed some trash. So last night was my first "new" Naxx raid. We killed Patchwerk on the second try, and Noth on the second try too. That was a guild first, and the first try on Noth only failed because we hadn't realized there was a door, and managed to lock out 2 raid members. We spent the rest of the evening on several wipes at the 4 horsemen, but I don't think we have the optimal strategy for that one yet. Do you split DPS in half for Thane and Rivendare, or do you put more DPS on Thane to kill him first? When switching, do you only switch tanks and leave the groups in the corners, or do the groups move with their tanks to minimize meteor damage? There are a lot of alternative strategies floating around for this encounter.
Anyway, I would say that my guild is pretty much typical for a raiding guild, not casual, but not Nihilum either. And for us the difficulty level was just right. Bosses don't drop on the first try, everyone needs to learn the various dances of where to stand and when to move, and killing a boss for the first time feels like an achievement. I could even see how more casual guilds would struggle with some encounters. So personally I think Naxxramas is well done, with a good design of difficulty level for the first raid dungeon. And it's big, so even if you visit it repeatedly you're not always on the same sequence. I like it!