Suggestions / Issues

[SirFist]

The game seems to handle editing of existing walls rather poorly now, there's no way to define indoors or outdoors without the foundation tool (that I have found) and this means if you demolish a wall within a building you will be left with a stretch of floor that is irreversibly marked as outdoors instead of indoors without reconstructing the room.
Example of outdoors zones as defined by the grass material after deleting a wall

The whole foundations system seems to be rather poor as it stands in general, if you expand an existing structure by building a new foundation off it and off an existing door the game doesn't seem to actually check if there would be an entrance already meaning you will be required to add an additional door which will you might not want at all.
Room which I would see as having a door when the game does not

I personally think you should simply imitate dwarf fortress in how you implement indoors/outdoors/foundations, simply have a roof option (perhaps in utilities) which allows you to place a ceiling as long as it is connected to some kind of support and have anything with 4 (or more) walls enclosing it along with a door and roof count as a finished indoor room.

Room removal is not really made obvious.

Placing and removing incredibly large room designations seems to kill performance (especially storage).

[catdevnull]

+1 to this, it's very difficult to expand early on because of this and demolishing/rearranging rooms results in unusable areas

[askiba]

Yeah, I agree. It's a bit finicky at the moment.

If it would check for connecting doors, that would make things easier.

Don't know how to fix the first bit, but I don't make inner walls via foundation. Creating brick/concrete walls is less nice looking but more functional.