I have been playing MMO games since i was like 8, and the overpopulation problems where always there. The thing is that usually this is fixed by dividing a server into channels sharing the same database (one server core and the channel servers), it has always been a thing, a good one. The screenshot below is from "Metin 2" a korean mmorpg, i thing is the best example, the channels share the same player database, same chat and you can always swap between channels just by relogging.
Something else, i think this game needs a launcher for updates and so, it would be easy for new/not so interested/casual players.
And that's all i'm just loving this game and i want it to be even better than it's right now.