In my opinion, vanilla was a better MMO than WotLK/Cata/MoP. And it's not nostalgia clouding my vision-- I log in to Emerald Dream every day and see the difference. And more and more people are starting to catch on. This is from right now:
But the Emerald Dream isn't perfect; there are many bugs and approximations. That's why I would pay Blizzard extra to put up official vanilla servers. If these guys can do it for free, then Blizzard can do it for money IMO.
Thank you for reading.