There has been a lot of talk about the class changes, talents and specs, but not a huge deal about the new zones. Just caught this gem over on FOH. A walkthrough of Karazhan.
http://video.google.com/videoplay?do...urning+crusade
For a 10 man this place is just massive. The scale of this stuff is huge. Looks pretty amazing to me. The scale between this place and somewhere like UBRS is just staggering. If anyone else has any videos or screenshots of the instances in the expac (especially videos) please do post them.
Edit: Library and Chessroom both were nice standouts. So was the Opera House. Would be sweet if the Chessroom had a special boss encounter where it was based like a chess match.