Breakfast Topic: What Will Become Of The Current Endgame Raid Instances?

Mike posed the question a couple days ago about whether a guild could keep it together come the expansion with having to balance all the new goodies in Outland with the current raid content. That kind of got me thinking...After the release of the Burning Crusade, and everyone starts their quest to level 70, what will become of the current endgame instances? Sure, the five man instances will still see action as people are leveling, but what about the big 40 man raids?

Before I saw the rather generous itemization Blizzard is implementing for the expansion, I thought that some of these raids would still be of some use, but now I am not so sure. Why gather 30 level 65s to hit Blackwing Lair when you can get equal or better equipment in 5 man instances or quest rewards in Outland? Sure, some people might clear these raid dungeons out for the the novelty of it, but even at level 70 clearing out Naxx or downing C'Thun is going to take some work, especially if you are not already experienced in the encounters.

Or maybe Blizzard could rework these instances so as to make them more appealing for people as they level. Perhaps nerfing the more difficult, intricate encounters, or rebalancing them entirely.

So what do you guys think? Will MC, BWL and AQ40 be ghost towns come the expansion? Or will people still make time to visit them after the Burning Crusade is finally released? Could Blizzard take some steps to make the content more viable?