I was thinking about mountains, dwarves, and improvements, and thought about which improvements would fit on mountains.
How about Mines (obviously) and Quarries? Mines being there for production and chance of finding metals/gems, and quarries being a small production and trade boost (maybe with a chance to find marble or stone).
After I thought about this I went and tested mountains, cities, resources, improvements and dwarven units.
Some things I've noticed:
-currently all dwarven units have "Double movement(or def?) in peaks" yet not a single one has "can enter impassible terrain" so it does nothing (no mountain climbing for them)
-cities cannot be built on mountains (not an option even if you get a settler on a mountain), BUT if you build a city then change the tile its on to a mountain in worldbuilder, the city remains and shows up on top of the mountain (sometimes takes a few turns for it to show up). Note: the main city tile has 2 food, 1 shield, and 1 trade like most other main city tiles.
-forests and resources can be placed on mountain tiles, but their yield is reduced to 0 of all types (food, production, trade). Resources look fine on mountains (pigs and sheep are so cute walkin up and down the ridges

)
-roads can be built on mountain tiles by workers (if you can get them up there)
-other improvements cannot be built on mountain tiles (not an option, even if you place a worker on a mountain tile with a resource), BUT if you create an improvement in worldbuilder (on a mountain tile with [or without] a resource) the tiles yield becomes that which the improvement would usually add to the tile. The improvement is visible and not bugged, though pastures looked bugged to me.
What I think would be nice for the Dwarves would be:
-all Dwarven units being able to "enter impassible terrain" so they can all go on mountain tiles
-dwarf settlers being allowed to build on mountain tiles
-dwarf workers being allowed to build Quarries and Mines on mountains
-mines adding 2 shields
-quarries (building them without a resource) adding 1 shield, 1 trade
-quarries on mountains having a chance of finding marble or stone
-mines on mountains as normal (chance of finding metals/gems/gunpowder)
-map generation adding occasional copper/mithril/gold/gems/stone/marble/gunpowder on mountain tiles, maybe even some tribal villages
-maybe workers being able to build windmills on mountains (a slight source of food), cause there's lots of wind up high in mountains
Mountain towns look so nice! A female dwarven leader might be good (I notice a lot of leader pictures are from icewind dale and such, and I know theres a few halfling/dwarven females in there as I'm playin it now

)