People need to understand that classic wow has nothing to do with legion or BfA - it is totally different game, only sharing the lore.
In my opinion, Blizzard needs to launch servers which are close in terms of characteristics to the alrdy existing pservers. After all the audience which Blizzard targets is the one that play vanilla on those servers at the moment. They need to do similar progression, patch the bugs and thats overall. I think 1.12 is the perfect version for the game, it is the more balanced out of the rest, with everything that vanilla offered, if they launch a new content every few months (3-4-5-6 - depends) it will be alright, people will have ~ 2 years to enjoy the game.