Was thinking about this recently, with all the hype around 25 man raids and the level bump many people have assumed that MC/BWL/AQ will pretty much fade away.
A thought though, Unless I am mistaken some of the enchanting/crafting recipe's will still be drops in there. I mean there will be better ones obviously from 60-70 but a lot of the original ones will still be good. And most likely the price on them will go down.
So since people will still want those recipe's I think that at least for a little while those dungeons will still get some use.
Another thing they could do is add some quests down the line that require you to get things from MC/BWL etc. "Farmer Joe lost his glasses next to lucifron last time he was mining in the core, could you go get them? I'll give you this spiffy sword if you do!"
Thoughts?