I recently read a post at Tobold's about the nature of Blizzard expansions, and it got me thinking.
I keep referencing World of Warcraft 2 in my posts ("Maybe Blizzard will change this in WoW2"). But it dawned on me that there's really no real difference between sequel and expansion with MMOs. We're already playing World of Warcraft 2. Blizzard is about to release World of Warcraft 3.
When I was raid lead in vanilla wow, I arranged and lead many many runs on Molten Core, a few on Blackwing Lair, and many in Zul'Gurub and AQ20. When news of The Burning Crusade's reduction in raid size came out, that the new raids would be 25 and 10, I cheered. My guild thought I was being sarcastic (a reasonable guess), but honestly I was thrilled. I still am. Larger raids are for masochists.