You were able to communicate with the opposite faction outside the game during Vanilla. We did on the forums all the time.
I don’t feel like it’s strictly about communication, actually to me it’s more about meaningful choices (e.g. pick your faction). Meaningful choices is a fundamental ingredient for a good RPG. Isn’t that what Vanilla/Classic is all about?
I usually like to make a character of both factions but if this goes through on non-pvp servers I guess I’ll just stick with alliance, without blood elves the only race I really like is troll. At least I like gnomes, dwarves, night elves and female humans.
So I’m not really against this if it ends up being the way things are. I know which side I like better, and if I want to play the other side I can always choose a different server, there’s not much reason to play opposing sides on the same server as other than goblin auction house shenanigans you can’t even really interact with yourself.
I might be slightly peeved if there’s only one RP server but I’ll get over it.