I think the endgame will be to introduce the “pristine” realms idea they’ve discussed in the past. These would be servers that run in tandem with retail but remove the groupfinder, CRZ and other convenience features for the purpose of facilitating server communities.
Because the primary thing Classic really has going over retail, potentially, is a strong community environment. It would be an interesting experience to see if they could take that aspect of Vanilla and bring it to retail.