1. A middle 4/8 way pillar holder for the tiles, especially the blank one. (I know I can get this effect with 2 3"x6" tiles next to each other but I would like it on a 6X6 tile for stability purposes)
2. 6" Diagonals for streets.
3. 3" diagonal (or whatever they work out to be) for both streets and sewers.
4. A piece two hold 2 pillars that are next to eachother together (both straight and diagonal). I know use larger pillars in that situation see my comments about geometry.
5. Pillars with odd angles of attack (most pillars especially the larger ones expect your walls to be a certain orientation on the tile, I want more options)
6. Tiles designed for stairs to be integrated into them (The only way I figured out how to do this was eliminate all the tabs holding the tiles together)
7.Slightly longer walls. Ones that can cross a tile with no tabs for a pillar on them.
I want to be able to build an * on one 6" board.
In general I want to be able to build tighter alleys that are more bendy than the current sets let me do. Right now it seems the sets look two geometrically perfect, which may be good in modern but psudeo ancient not so much. I think diagonals can help to break some of those lines up a bit.
1895 hydraulic plunger freight elevator by Otis Brothers. I believe that they are still very much in business. (As in the biggest elevator company around.