Yeah, I know it's already on the cores to add some better graphics to DF but I want to suggest a way to do it which would make the game more moddable than usual.
I suppose that Toady probably has a data structure which represents the fortress or the environment and he reads it in order to translate everything to graphics. The current problem with the tilesets is that Toady uses the same code to represent several distinct objects. This makes me think that when he reads the data structure what he gets is the ASCII characters directly, which he turns then into tiles to display. So in a read the engine might get a dwarf character and in other read he gets a character which represents his/her status.
My suggestion is to scrap that and instead let the structure be readable more openly. By this I mean that if I read what's inside a cell. Instead of just getting an ASCII, I should get several variables like for example an integer code representing the specific object and others that could represent modifiers. That way, for example, instead of receiving a dwarf character sometimes and other characters to represent special statuses. I could receive the integer code representing the dwarf alongside other codes representing the different statuses (like injured and the like) all on the same scan. In the case of several dwarf/objects piled up in the same cell, the information could be conveyed in a single read as a list.
The idea is that the graphics engine, which should be separated code-wise from the rest of the code, should read this data and turn it into graphics. But, more importantly, this graphics engine should be easy to replace by other custom engines made by modders so that they could device by themselves new ways to represents the game data visually instead of just replacing the tileset. This way some modders could device an isometric tile view (which could display several z-levels with isotiles on the same view) or even a full 3d engine. They would only need to read the data of several z-levels from the game and turn them into graphics whichever way they want too.
This occurred to me as I watched a mock-up made by one poster on the penny-arcade forums which represented DF in a isometric style. I was going to show it but the image went puff 
Author
Topic: Graphics and Tilesets. (Read 7331 times)