There are a lot of different skills in the game. Some of them have not yet been fully implemented, but some, in my opinion, do not make sense. This applies to work skills such as Butchery, Gelding, Milking, etc. I suggest to completely remove all skills that do not affect the quality or quantity of production and replace them with labors, similar to hauling. Instead, it is possible to introduce general skills that will be responsible for the speed and quality of such low-skilled jobs (as it currently works with military professions). An example of such skills: stamina - will display the fatigue of dwarves who can leave the current task unfinished at low rates, dexterity - affects the speed of work. The main influence on these works from the physical attributes.
Probably some skills have to be reworked (fisherdwarf, brewer, miner).
A more complex idea with the addition of different strata of the population and families belonging to these strata.
- The low-skilled dwarves from the example above ~20-40% of the population. They can do all kinds of work. After receiving the skill of the 6th level, they change their rank and get a profession. Cannot be a target of strange mood.
- The middle-class, which can be divided into 3 castes: military, crafters, intelligentsia. They are not available to perform low-skilled work, will receive negative thoughts when resting in the same tavern or training in the same barracks with ordinary workers. With the military and crafters, everything is pretty clear. Doctors, architects, performers, tavern keepers, scholars can be attributed to the intelligentsia.
- And the nobles (except for the expedition leader). All types of work are not available for them (as for children), with the exception of the main specialty. Trading for a broker, management, only education and training for squad leaders. Priests should probably be included here, and add similar ranks for scholars and guilds. They will mainly affect the morale and speed of learning new skills in these zones. Barons and kings and their children are just idlers.
New goals for dwarves to improve social rank, appropriate reactions to communication between different sections of the population, etc.
Add behavior to children - from time to time follow the parents and learn from them. After reaching adulthood, they should join the respective ranks.
Add families (with their own surnames) that will represent their segment of the population. When status changes, a new family with a new name is founded, this mechanic will primarily affect children. A new family with own name can also be created after performing some deeds: creating an artifact, killing a megabeast, changing status. The name may reflect this act.
In many cultures, last names have some meaning. In Iceland, there are no surnames at all, only patronymics (Urists[son]). In many countries, surnames are derived from the father. For example, in Slavic countries they are formed by adding a suffix. Different nations have different sets of suffixes (Russia - Urist[ov/in], Ukraine - Urist[enko/uk], Poland - Urist[ich/owski]. Nicknames, professions, etc. are also used. But it can be difficult to keep unique name for every dwarf. So such system needs to be improved or have additional checks. No need to change name of a spouse. But in most cases they have to be from the same class.
A few thoughts about reworking of skill affect on speed, using the example of mining. My idea is adding a base excavation speed that cannot be exceeded and will be achieved at skill level 5-6. Further increasing of the skill will reduce the penalties for excavating more difficult areas. I read somewhere that the developer does not want to add the influence of the hardness of the rock, but you can add complexity depending on the depth of the excavation (this will reflect the engineering difficulties of the work, building mines is a science) and/or the type of tile (soil/stone/vein/cluster). A higher skill will reduce mining time multiplier down to 1.
Similarly, you can change the crafting time by adding a difficulty multiplier to some types of work, reaction difficulties. It looks rather strange when mason hardly rise the first few levels of the skill and then suddenly starts making one stone block after another, instantly becoming legendary. It's also a good idea in the Masterwork mod to have an extra stonecutter workshop in the production chain.
And finally some words about trade
The current balance is rather weird, especially when it comes to trade agreements. Some basic resources have many different materials (stone, leather, metal) and some do the opposite (cloth, silk). Also, some things are brought in containers (leather), some in stacks (meat, cheese). As a result, you can order a huge amount of leather (the industrial production of which is unreal now) but let's say it is impossible to import coal normally.
Accordingly, the idea is to add special containers for all kinds of resources, including stone. Add an item mass multiplier for the price, which will increase the cost of buying and reduce the cost of selling. Orders in a trade agreement should be made for entire categories, not specific material. This option should remain, but it will only change the distribution of goods brought in by material and not the total quantity. Reduce the cost of exporting food (perishable goods). In other words, make a price multipliers for certain categories of goods and they should be different for export/import and even civilizations.
There are other ideas about trade: traders come from specific cities, bringing the appropriate set of goods, materials, give only a quarter of the price for goods available there. Ability to send own caravans to others. Separate caravans for trade agreements in large quantities. This will allow to make new specialty of the fort with large numbers of trade deports. Contracts on military protection of trade routes. But all of this needs to be thought through in detail and will require a complete overhaul of the current trading system but can be really interesting.
Sorry for bad english. Mostly done with google-translate and edited a little by me.