Here is in general what I feel should be added in to DF;
Groups: Civs have values, civs have customs, civs have constitutions and laws, civs have, institutions, government agencies, civs have religions, civs can own items, land, buildings, people, and intellectual property. Civs can be Communists, Capitalists, Feudalists, Theocracies, Republics, Democracies, Monarchies, Constitutionl Monarchies, Anarchists. There is civ and site government which are of the same type so no Capitalist civ with a Communist town of St. Georgia.
For religion it has to do with the values of a specific civilization and if a certain religion conflicts with them or if the population is lied to like and told it conflicts with them (People can also lie about a certain race being savages to cause a racist value to exist in a government) like Hitler so a certain value might be the outlaw of a certain religion in this case Judaism and the Hebrew and Judah race this could also happen for homosexuals or certain fetishes.
Make it so racism, sexism, and religion acan be civ and religious values cough cough AS ANYONE WOULD EXPECT FOR A GAME LIKE DWARF FORTRESS cough cough. This way a civs or sites value is determined for racism is there is a coin flip for arch-race (Elf, human, dwarf, goblin etc) discrimination being a thing or no. Another way is if what people are in power and if they as individuals are racist or how many sites have racist government or majority racist populations etc. If yes there can be no more than 2 accepted arch-races or only 1. Then there is a coin flip for discrimination of traits of individuals of allowed races if yes then dice rolls for what traits are deemed allowed or superior (which is another dice roll)for example skin color, hair color, eye color, height, ear length, nose size ect.
Add castes, so certain professions get more respect than others, so lets say a pump operator or hauler are a low caste and are not aloud to vote and are not respected much. While a miner, smith and military dwarf are considered high castes with renown and repect and if they vote there vote is worth 2 of the lowest caste allowed to vote. This could be a civ value or a religious value. religions and civs are coded the same. But civs always have higher priority of power unless a civ in a theocracy. So a civ with a no killing value will veto a religious value of the killing of members of another religion, unless said civ is a theocracy.
For leaders being chosen make it so it by heritage, by force, by challenge of mind, might or skill, by vote (In some civs children can vote in most not, sometimes certain races cant vote, sometimes certain members of a religion cant) by choice of another entity for example the current king chooses the next or a deity chooses the leader, or random pick of a Dwarf. In some civs child labor is a thing. Make it so there are certain rituals that must be performed so a Bishop must drink from the water of a certain holy ground to become Pontiff. So lets say that ground is taken by enemies chaos ensues since no new Pontiff can arise. Or a royal must be crowned on a certain artifact throne to become king but if the throne is stolen the kingdom erupts into civil wars.
Trading: Trading should be based off negative and positive point system between specific sites and civs as a whole. And is self explanatory what effects it seeing as what I've already talked about.
Systems: Torture. More info about items, thickness, length, actually where things are engraves on. Do the same thing for entities too. Make it so you can read books. Make it so dwarves can write and share music, give dwarves memories of smells, sounds, colors, places, ideas, items and people they remember which the player can look at. Intellectual property. Give entities fetishes, height, body part, skin color, animal people if there furries. Add in pedophile dwarves too. Add in pronouns since if there are idiots in real life there must too be in DF. Why not have it be a thing of certain civ or religion customs. Make it so pleasing dwarves is trickier and give a reason to make items for dwarves of a certain matierial they like or something to stop them from tantruming. Becuase at the moment its too easy to make dwarves happy.
Items:
Pots, Cooking pots, pans, trays, shifting pans, tablets.
Weapons: Sabers, scimitars, rapiers, glaives, Japanese swords, gladius, arming swords, long swords, short swords, great swords, zwiehanders, dane axes, curves swords of each variety, war hammers one sides, war hammer 2 sides, war picks, war hammer plus war pick all of these in 2 sizes, trebuchet, catapult, ring axes of 2 sizes, crescent axes, war shovels, slings, giant slings, giant sling shots, great bows, staves, muskets, puckle guns, Gatling guns, musket revolvers, cannons, grenades, beenades, liquid grenades, Holy Hand Grenades that serenade, gas grenades, Molotov cocktails, semi auto rifles, bolt actions rifles, air rifles, spring rifles, automatic rifles, multi barreled rifles, rotary cannons, artillery, rockets, incendiary, HE, High Velocity, AP, tracer, liquid coated bullets, standard, rubber, magic, blanks, and hollow point ammunition types.
Spells: Look at DnD CRPG's and Dark souls spells and Elderscrolls spells. A portal that opens up to the arrow dimension and arrows fly out. Do the same thing with bullets. And swords or potions, any small items.
Performance: Thread support (I know this is impossible at the moment), GPU support.
Misc: Add in a default world that looks like earth. So all the bioms are the same but not areas them selves.