Most classrooms are useless. There's no reason to make students come to lecture every day when the lectures could be recorded and put online. Most of them ARE recorded and put online, in many schools. I mean, it's true that you can't ask questions and stuff, but the benefits of being able to pause a lecture for taking notes, re-listen to parts you didn't understand, and so on, far outweigh being able to ask questions which you could just as easily email/im to the professor/TA.

Myself, I think it'd be a better idea just to have a few lecture hall style classrooms where you can come and get help with homework (it's hard to show someone how to work out calculus problems over the internet, with current technology), or take tests, etc, and put the actual teaching online.