If I'm waiting to get my world file fixed, to remove a impassable blockage, can I keep playing in that world or do I have to wait for it to get fixed?
I can't speak for Josh but if it's just a chunk with some impassable slices then that chunk file can just be replaced with a correct one at any point and it will be fine, so long as it's not from a later game-version than the world file (that would lead to strange and wonderful problems; more strange than wonderful).
For that matter, if you get the chunk ID and region ID out of the debug info, you could find it inside your world folder and:
1) Leave the chunk.
2) Wait at least, say, 20 seconds to make sure it's been dropped to disk
3) Delete the chunk's .datc file from the disk
4) Re-enter the chunk in the game; the missing file will force a new chunkgen which presumably will result in different slice selection (I'm not certain of that).
There's also the Ctrl+K dev keybind for re-gen'ing a chunk but iirc that deliberately tries to do everything exactly the same unless there's been a gen-logic change since it was created. And I dunno if it works in the non-dev context.
However it occurred to me that the world file might be an evolving file, like it would be in Valley 1, rather than one where everything is generated at the start of the game.
The world.dat is somewhat evolving in that player entity info, npc info, and some other stuff does change but all the regions are generated at the start. The regions.dat file actually has all the region data anyhow. It can change for a variety of reasons (including player transformation of tiles) but it's not generating new regions mid-game.