The Karazhan Mistake?

Foton has taken a look on Blizzard's comments and argues that Karazhan is popular because the shift to 25-mans is too hard.

I've touched upon the subject myself and there's a discussion about raiding on my realm's forums. Although the approaches are different, the identified problem is the same: It's too hard to move on from Karazhan. WoW Jutsu's statistics confirm this. 66% have cleared Karazhan, but the popularity of the instances drops very rapidly after that. It's not that Karazhan is popular, it's the only choice for too many.