I would like to suggest the addition of one more special wall/floor tileset for wizardlands and mysterious portals. Specifically, it would be cool to see a tileset where the wall designs look like a starfield instead of walls, thus creating the impression that the rooms and corridors are hanging in space like in that one level of Diablo II that the wizardlands are conceptually similar to.
Although I don't recall a level like that in D2, I like the idea. You could do that for a wizardland or other dimension. Before I read your post more closely, I actually visualized the walls as looking more... futuristic (like the inside of a space station), and make the area between the walls be empty with a star field behind it (like the level is somewhere on a space station. You can't cross it normally, because there's nothing there but space. It would also explain where those aethernauts come from (or whatever they are called). Anyway, my version is just a slightly different take on the same concept.
The primary questions to ask about this are, firstly, are you aware of the amount of work that goes into a tileset? And secondly, do we know if we can animate tilesets? None of the existing ones animate.
Dungeon objects can animate. (folder /dungeon/.) Tilesets cannot. It would have to be static. (...assuming a modder wanted to do it, that is. We're all pretty focused on clockwork empires at the moment.)
I was going to try something like this, actually, as a reference to the Arcane Sanctuary in D2 but 1. the 'liquids' (animated dungeon floors) are a really brittle system; they go back to some of the oldest parts of the game, I believe, and are just awful to work with; 2. the dungeon generator assumes all space not part of a room is filled and solid. It'd require a special case for dungeon generation that would almost certainly open up a lot of holes in assumptions made in how dungeon rooms work. Best bet would be to just make really big rooms. Short answer: It'd require a lot of special-case code to do right and that's why we didn't do it.
I think the level 4(ish?) tileset is kinda futuristic, so that will have to suffice. My memory of D2 is limited to flashes of a desert landscape and a volcanic hellscape. It was never one of my favorite games, but I had some fun with it for a bit (I probably just didn't play it as much as many other people -- I actually lost interest in it before the end, which is pretty typical for me with action-oriented games.
