When were the "leashes" applied to all mobs?
I have absolutely no idea for Vanilla world bosses.
BUT im 100% sure i could kite Overlord Mok Morokk to Orgrimmar in Wrath of the Lich King...possibly Cataclysm.
I did it for a while.
I was kinda addicted to this activity as a kid and did it for a long time...but my memory is failing me...not sure if i did this in Wrath or Cataclysm...
EDIT: And how is it in the Beta? For anyone inside beta.
EDIT: Asmongold did kite a world boss to stormwind and killed everyone, so its still possible for how long? who knows #nochanges