Well, this is nice topic. You've been working on this and precursors to this for years, I think...
On minimap, maybe use 1x1 tileset?
ex like this abandoned one. Looks better than the in-game minimap, I think.
With next version, I expect there's more interest in multiple concurrent forts in the same world as well. (Pausing, tho...You've handled it not bad, at least. And making self-sustainable fort is not something that requires lot of resources, thankfully. Maybe a well and one locked in (were/vampire) dwarf farmer who drops down plump helmets through a hatch.)
On screens, you probably know - if not wrote - gui/dwarfmode, but worth mentioning for others as an example. Multiple screens was something that the dfterm ideas lacked; I've played with multiple players sending inputs to 1 df but only 1 screen still, and it still means taking turn for all but painting designations with the mouse.
If you're sticking to single controlled dwarf and have to make controls anyway perhaps hook it to Armok Vision (on client's computer). Would also allow server to run without having rendering take up cpu space, leaving more fps for multiple players.
It'd be kinda like 3D MORPG at that point.
(Easy to say, hard to implement.)