The reminder of the debate actually sort of got me thinking in a less controversial vein. I myself scaled back my game a bit from original WoW to the Burning Crusade expansion. In the original game, I was a relatively dedicated raider. Not the most uber, and probably still more casual than most, but I did regularly participate in 40-mans and tried to bring my consumables and my resist gear and be on time most nights.
However, with Burning Crusade, I decided to retire from the raid game. I felt I was just spending too much time farming stuff to raid, I had more real world obligations to deal with, and I felt that spending 2-3 hours in Ahn'Qiraj or Blackwing Lair 2-3 days a week just wasn't how I wanted to spend my playtime. So, come BC, I decided to stick to 10-mans. Not that there were many, but I figured Karazhan would be about the pinnacle of my game for BC, and that was just fine.
So, anyway, here's my question: Are you or your guild planning to scale back your game for Wrath? Are you dropping 25-mans for 10-mans? Retiring from Arena play? Dropping out of raiding altogether? What reasons have made you decide to try a new slower paced playstyle in Northrend?