One of the things in roguelike development is that you should be careful about implementing too many ideas. But what if you did implement all or most ideas you had? I started to think about it and it could be something to try. At least with Kaduria, because I really don't have any kind of pressure to release it any time soon.
One idea I had the other day is a randomized cargo lift. With that it would be possible to move something heavy between levels, like 'movable' objects (barrels etc.) which you can't pick up anyway. The source and destination levels could be more or less random, making it interesting sub-plot to find out which lifts are connected.
I've started to change notation type enums to namespaces the same way I did in Teemu. It's not very important, but makes the source code more manageable I guess.