Have you considered playing past the sleep walk eras of the game?I've done the big guild thing on the past few TLP servers, Classic through LDoN, and I've learned a lot about the game that I didn't learn the first time around (1999-2003). At the end, though, it felt a bit too easy to defeat content with 72 very well-geared and mostly well-played characters
I am not saying the game gets hard, but for people and guilds who havent done middle era expansion and beyond, they can be challenging to learn some of the raids along the way and defeat them as they become less tank and spank, and more mechanic reliant.
Truly from classic through LDoN there isnt a single actually interesting raid. If you feel things are too easy find one of the many raiding, but not top end big dog guilds on a TLP and stick with them past the 1 button era and into the 2 and even 3 button eras.