Helpful! Though usually it was just one floor that would be a little wonky, or even sometimes just one wall. I don't recall if I found those hotkeys in the keybind list, but I do remember fiddling with what I did find and not being satisfied.
In one case the placement of the stairs was almost almost perfect:
The "stairhall" is pretty useless (it goes down to the cellar/basement, occupies the largest room in the house, and isn't even redibly accessible from the kitchen), but the thing I noticed first was the useless corridor that would have worked perfectly if the stairs to the upper floor connected to it directly (basically mirror that 1x2 room and open it to the west instead of the north).
There was also this house, where the only way to reach the upper floors was via a secret passage (???). The other stairs go down into the basement. It also leaves that central room weirdly shaped.
Or there's this house where one room is only accessible via its two neighbors. Most houses don't do this, because it creates a bedroom-like space that has no privacy. That said, a town house my dad owns had a room like that on the 2nd floor: the stairs came up from below along the south wall, with bedrooms to the east and west, the central area at the top of the stairs being open to both exterior walls. Couple friends of mine in a completely different city an hour away had an identical layout, except it had a wall that separated that space from the stairs (creating a hallway), which allowed it to actually serve as a(n admittedly small, but still usable) bedroom or office.
This one's trivially fixable by splitting the living room in half vertically, then merging the left half with the room just above the entrance. It was the only thing wrong with it.
Additionally, as the ground floor stairhall was essentially the same, just 3 tiles tall instead of 2 (with a 1x2 bath in the remaining space), you could shift the stairs one tile north, which would let that stairhall be a 1x2 on both floors, creating room for another 2x2 on the lower floor out of its excess space, and adding a 1x2 bath on this level from the same.
Or you split that room above the entrance in half horizontally, turn the part with the doors into a hallway/corridor, and turn the other half into a bathroom that connects to either the hall, the living room, or both.
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I realize allowing more fine grained editing would be a fairly large task, but I honestly went looking for other applications that would do both random generation and editing, but I found... nothing. The only other random generators I found were worse (in all respects, and still didn't have editing) and applications that allowed editing were either very basic (visually speaking) or lacked other features (like different floors).
https://floorplancreator.net/ was the best. It's still lacks decent visuals (no textures, just solid colors, but also strangely high poly models, and in some cases, strangely small default sizes--like the toilets are a third smaller than the smallest possible in the real world). And while it had a 3D view... it didn't have roofs. So if a floor was smaller than the floor below it, it just left this gaping cavity. Also some other minor UX complaints, like inconsistent snapping or settings buried inside submenus, but overall a decent freeform editor.