One of my main concerns about Battle for Azeroth is: after getting Tier 3 armor on your WoW Classic character, will it become account-wide transmog for main game characters? Same goes for other unobtainable transmogs and mounts from Vanilla.
Personally I hope this is never going to happen, it would massively cause people to play Classic just to get the unobtainable transmogs and perhaps ruin the Classic experience for everyone else.
Also I wouldn't want to see some random bads running around in one these marvelous looking sets. BMAH is a good gold sink, I myself deleted around 4 milion gold from the flow because of it. However Blizzard tends to cater crybaby bads and casuals, so I think it is defently possible.
What are your opinions and predictions on what is going to happen?