There are many debates now, whether Classic servers should be "fixed" or not. What if Blizzard just will release "fixed" version of Vanilla leveling as option for live servers? I would love such solution, as I don't need Classic servers themselves, but would like to level in pre-Cata variant of locations, that weren't destroyed by Cataclysm.
You should understand, that Blizzard will most likely port Vanilla to current engine anyway, cuz it's easier, than fixing all Vanilla's bugs and exploits from scratch, and Blizzard may agree not to fix some balance and design issues, but not bugs and exploits. Therefore it wouldn't be so hard to implement Vanilla leveling on live servers. This also will prevent Classic servers from being complete waste of resources, as I really doubt, that many players will play on them in a long term.
What do you think? Great compromise?
NOTE: Ok. I decided not to interrupt your discussion, but I actually meant "Vanilla's locations and quests on live servers" - not "Make leveling on live servers as hard, as in Vanilla".