Ok lets say you randomly generate the city, it looks pretty decent but you want to edit things a bit.
By hovering over a structure you can add or remove floors one at a click or something along those lines. I think that would be the highest priority function for a novice user.

As a Novice user the things I'd like most to be able to do are.
#1 Increase/Decrease structure by clicking on it.
#2 Changing the structure type

As a more Capable user
#1 Change terrain elevation
#2 Move streets around. Maybe even add remove.


I think if those 4 functions were in the program, it would suit the needs of almost any GameMaster, of most systems.

Wishlist for Advanced would be coast and river editing, along with piers, docks and bridges. But the 4 I've mention before, would be more than enough for my selfish DM'ing needs.




On a separate discussion how would streets be editable, would they be like nodes of most art programs, where you could drag them around, along with add/remove?
That would really add an amazing editable ability for the users.

I hope I'm not overly bombarding you with stuff, like I said before this is probably the most useful program I've seen being developed.