So one thing I have to say right away, each major “Region” of a Planet (like a Big Island or so) will have its own World, simply for management Reasons, and so that Servers can do things like Clustering properly (I plan to test that with Raspberry Pi’s by the way).
This means a lot of Stuff regarding Region Boundaries, since when you cross them you need to be moved smoothly from one World to another, you need a good transition especially with the Physics (that’s why Islands is gonna be the first non-debug Worldgeneration Type, because you can mostly ignore that Issue for swimming people).
And I did talk a lot about this problem with @OvermindDL1 , and he said it is “easy to share a database between servers”, whatever that will mean for the transition between Regions.