Messing with maps...

Heh, I say "may" because the only testing I did was some eraser wagging and a quick look around.

That being said, as many places they have tiles like that, and the way they always look like junk, AND how they seem to repeat (many of the same tile) if you really wanted to, and knew how it worked, it might be possible to reuse one or 10 of the same filler tile and remove the rest?

Be next to impossble to find all the code that calls those tiles probably, and over all not worth it. Personally I'd stick with deleting tiles I knew exactly what they were for. Last I played with the map editor, and Madsiur's map patch, seemed like there were several maps/rooms that could be optimized (moved loser together and still not in sight range). Then even more that rooms that could be tweaked (adjusted dimensions) to cram in tighter. Then you could relocate rooms from one map to several others and free up a new map without loosing rooms. Still have to mind the tilesets and such. As well as the NPC limit per map (ran into this many maps...)

I'll shut up now, I'm just confusing myself at this point.

How these tiles are called though... would be interesting to look into, in theory couldn't it be used to mix and match tilesets?

Another option altogether (something I'd like to look at eventually) is using code to change/morph the map based on event bits. (As in opera house stage, I think, and how the floating island is removed from the world map after it rises). With a big enough block of code, I still say you could create an extra (morphed) world map. Some creative use of monsters and events... I still think it would work.