Blizzar are masters at stalling things. And sadly, they will never open Legacy servers, not now, not in 3 years, not even in 10. The reason is simple, once they do this, their playerbase will start to spread, some in Vanilla, some in BC, some in Wotlk and so on. This means once they would open Legacy, there would be too few players on the live-retail, to actually worth future expansions development and the game will... well... die. They can't risk it, at least unless the subrcribers numbers won't fall it REALLY bad.
What to expect then ? The biggest change they might announce is at best the crappy Pristine thingie, mening on some servers they will allow people to cap to 60 or 70 or etc and allow only that specific content, be it Vanilla, BC or higher. Blizzard's plan is/was/will be always the concept called "Carrot on a Stick", meaning they will do anything possible to lure people (read lie) into believing that they are listening and they have a plan.
Actually, they do have a plan, and the plan is to stall, telling once in a while the community that they are STILL thinking about it. But think about it yourselves, what's there... to think, really ? Think about what, they have all the data needed, all the infrastructure, all the programming power, original code, everything. I bet they could open 2-3 vanilla servers in tops 24hours if they would really want it. Their programmers anyway are payed and hired and ready to do whatever the chiefs dream about.
So think about it, they closed Nostalrius and did absolutely nothing after, no matter how hard we pushed with our petitions, with out cries, with our everythings. And now, they just made a statement, almost 1 year later, that "they are still thinking about it". We both know what this means, aye ? So what to do ?
Pray for Nostalrius' return, really. Pray with all your power, ask them to do something, support them, make them understand they are basically the only people in this fucking galaxy who can actually deliver what we need. No contest about it, just look at Kronos, Elysium and other servers, they don't even come close. I logged today on Kronos to see that I can't land a bloody cheapshot cause of insane lag, they had lag 2 months ago too, they were shut down by dunno what ddos crap, it's obvious that such project is a hat way too big for their heads.
TLDR: It's gonna be Nostalrius or nothing at all.