Migrating selection from world A to world B

Problem:

In late game when players have elytra and plenty of fireworks for travelling great distances, an update to the game may be difficult to experience since so many far-away places have been loaded/explored and are exempt (sometimes) from having the possibility of the new updates.  This is bothersome since many old worlds hold sentimental creations for players, and creating a new world to experience the updates is not more desirable than keeping their creations.

Idea:

Add a block type, perhaps something like redstone, which when connected back to itself (like a circle, but allowing bends and curves) selects the enclosed blocks from bedrock to the build limit.  This enclosed selection is saved as long as the loop stays closed.

Add an option to the UI world selection screen which says something like "Migrate and Create World".  This button would allow the user to select an existing world wherein a loop is closed and saved, and then it would take the saved selection from that world (the enclosed volume) and create a brand new world with the saved selection placed into the world at or near the spawn point.

Result:

The ability to take a specific selection from World A and migrate it to World B allows the players with sentimental builds to save their primary creations (for example a city, or a house) while still experiencing the full benefits of future updates since areas outside of the migrated area will be unloaded and unexplored.