This has been an idea nibbling at the back of my mind for quite some time. I have always cherished the thought of experiencing all of the older content, most of which I did not have the opportunity to play when it was current. I used to trawl through top private server lists searching for at least ONE viable server just to experience the PvE and PvP of the times.
I feel that Blizzard has nothing to lose by simply implementing old patches for new clients to launch Vanilla, BC, and WotLK servers, and that it would be a MASSIVE popularity boost for WoW in general. I mean, after all, all we see nowadays is complaining and whining about how they miss older WoW eras, how Blizzard is ruining the game, and the like.