For starters, is there a reason why the map does not use tiles? It wouldn’t hurt to at least have the option of a square tileset with the ASCII to neaten it up a little.
More important to me, however, would be the ability to put down more than just a yellow N for notes. How about a bright red X on a dark red field when you need something to designate wasp houses, or intersections sprinkled with landmines? Maybe a bright green O on a dark green field to mark safe houses, or a military truck that only needs a little gas to get rolling again? Perhaps a black C on a dark gray field to indicate that a particular building has been cleared of all items?
I love that cellars have become a lot more frequent, but it’s really making my map get very cluttered with all the “stairs down” notes if I don’t delete them, and it’s silly that for a game built around foresight and planning, our map management is marred by the limitation of only throwing down an ugly yellow N for any and all notes.