This has been probably brought up in multiple (and the most meta) shapes, ways and forms before, maybe even by myself, but whatever, here goes nothing...
This probably does tie a lot into magic more than anything else, but one of the cool things that probably just about anyone wanted is to allow travel between generated worlds.
You have Urist McChronos who comes from world X. You have also generated world Y.
You take McChronos from World X, some unspecified process happens and he ends up in world Y, at an unspecified location.
Could be both cool and problematic if we throw modding in-between, but I would imagine that for things like bodyplans and materials the game would pull the information from world X and put in in a temporary .raw file, me thinks.
That is, if one even modded the game in the first place.
I mean, think about it - a world-traveling legendary conqueror wielding artifacts stolen from many different worlds made from exotic materials and having other strange properties?
Even if it would be done in the most meta way possible ie. fiddling around with the files, if only for the first release of that particular feature.
And I guess that making this a feature available for NPCs (beyond companions) is out of the question beyond some really redundant and frankly pointless work.