[WIP] "The Underkeep" iso Dungeon Map & Map Tiles

[Morgan]

I think the previous choice of drawing walls only on the far side is better. What you want to show is the interior of the room, especially if you plan to use some textures to give a sense of color.
If you want them to be less invasive, I think loogie's idea is good, 100% opacity at the bottom and it fades as the wall rises.
Then, perhaps I have a solution for the corners, and this SHOULD allow you to use narrow corridors too:
Instead of putting the wall on the whole side of a room, stop a square before the last. Then, draw some "angle" pieces that cut the wall rectangle into half.
Aww, trying to explain this is more difficult than drawing, here is a sketch of what I intend. Sorry, it was handmade in 15 seconds, so it looks... well, not worthy of a cartoghaper!

Hope this helps!