I'm all for them being linked together seamlessly in the end, but such a system will take a lot of learning, practice, and if not done slowly/carefully a lot of pain lol.

It's easy to say there should be a smart system that lets people play with who they want in a beautifully dynamic world that can also handling some filtering (like the English speakers probably want to be with English speakers, the Japanese speakers with Japanese), it's actually extremely talented to pull that off well. Like I think WoW's phasing to have super dynamic zones is a SUPER cool idea (that FFXIV uses on a sort of similar but sometimes less 'big' scale), yet phasing has had some issues and particularly when it first came out.

Good luck