1. glowing furniture.
There's no flag for a piece of furniture or terrain to produce light. The 'utility light' terrain produces light, but it seems to be hardcoded. Terminals produce light, but they don't work in a generic mapgen tile. I mostly need this for NPCs. They only react to sight, so a player can sneak up to one in the dark and shotgun him in the head repeatedly. Having light sources scattered around will make that much trickier to do. There are ways to fake it like placing active flashlights, making one-tile vehicles with floodlights, or mapping wood, fire, and braziers to a single tile, but a simpler option would be nice.
2. optional palettes
I can do cool stuff with the new palettes, especially by mixing several, but it's just a list of all palettes used. If it could also choose one from a list, that would make combining them more useful. Sort of like item groups now, how you can mix collections and distributions. For example, I could make a generic store room that used a base palette for the walls and floors, and then put rows of X's on the map that weren't defined in the base. Then the game would choose one from a group of a few palettes where X is mapped differently. So, one would place refrigerators and food on X, a second would place crates and explosives, a third would place lockers and guns, etc. It might look like:
"base_palette", ["food_store", "explosive_store", "gun_store"]
That way, instead of having three nearly identical map tiles, you could have one maptile with a few extra lines. A better example might be labs. They could swap furniture/terrain so an electronics lab would have machinery and terminals, a mutagen lab would have cloning pods, a teleporter lab would have teleport pads, and the loot and monsters would all change with them. And by combining a few sets you could have stuff like:
"base_pallete", ["food_store", "explosive_store", "gun_store], ["open", "locked", "defended" ]
3. adopting guard dogs
(Probably not "minor" since it involves NPCs.) There's no way for me to add monsters that are friendly to NPCs. Specifically, if I make a bandit camp, they can't have their own guard dogs and turrets, who all like each other but not the player. I thought I could mod in a friendly monster with a different faction, but it seems that monster factions and NPC factions are totally unconnected except for the "player" pseudo monster faction. There is already a way, in a map gen json, to make a monster friendly to the player, but no variable like, "faction": "hells_raiders". This will also be a problem for weirder things like cultists who should be friendly to nether creatures, Carriers who should love the fungus, mutants who should be friendly to CHUDs or their animal type, tech guys with robots, and other things where monster and NPC factions should get along.