The status is that currently, MMO players are finding out vanilla is a good game, if not the best. The number of players seems to be a constant 50,000 right now and this can increase further. It is unlikely to go down due to crap offered by modern MMOs.
Blizzard will not offer legacy servers, they will focus the discussion on pristine servers and maybe release it as a patch of the Legion barf they're producing. The developers will try to 'tune' the levelling experience. None of the many other lessons learned in vanilla will be applied by Blizzard in the foreseeable future.
Vanilla projects will become more and more professional, as the level of emulation and code increases. DDOS protection and virtualization will become better, vanilla private servers will start cooperating and offer transfer services more and more. Until it competes with retail. THAT IS when Blizzard will wake up and support legacy servers, for free. Since we will have forced them to.