A more in-depth explanation of how personalities and values impact unit behavior overall, especially in worldgen, would be nice. We've had the values and the ability to modify them for ages, but apart from speculation very little is actually known about what they do. I've been using DFHack scripting to scan average personality trends of units that have been involved in certain events, but so far I've found no statistically significant impact of personalities or values...but generated necromancers have modified personalities, which suggests that personalities do something.
That's kind of bypassing though the acknowledgement that they are transformed beings, who used to have lives & personalities of their own and whatever the tower's own hardcoded faction has in place of upheld values. Currently in one of my fortresses there is a necromancer occupied (not destroyed) hamlet populated by precisely >1 unit ready to be investigated if i find any resistance with its own site-government and everything seperate to the tower.
It's not the best method, I'll admit, especially since worldgen seems to unfold through butterfly-effect-like event-based chaos. I was hoping there would be something obvious, like position holders having above-average AMBITION or PRIDE that motivated them to reach that position or something, or book writers placing greater value on KNOWLEDGE, but a census of almost every significant worldgen role I could think of (position holders, necromancers, authors, army leaders, necromancers who raised ghouls, etc.) revealed an almost perfectly average overall distribution of personalities and values. Of course, if there's a more complex process involving the interactions of multiple units and every personality trait had potential to cause a unit to ascent to power in particular circumstances, finding global averages wouldn't reveal these. Sadly the details of how particular individuals rise to power, apart from the fact that it probably is related to social skills, still is very much a black box.
There is almost definitely some effect of personality and values when scanning an individual's deeds once they achieve power - there's a notorious law-giver I've examined who had been involved in ordering a number of religious persecutions and wars, and sure enough has low TOLERANT and high VIOLENT and VENGEFUL values. But things like that are just anecdotal evidence - which traits are actually causing which effects? What is the point of making all necromancers have lower TRUST and higher ANXIETY_PROPENSITY, and does it have anything to do with their tendency to wind up in positions of power? Or are these events just random and I'm paying attention to the details that make sense while ignoring the ones that don't? Without a better way of scienceing out general trends, or a statement from Toady explaining what all of these personality traits and values
do, it's all just guesswork.
I crave data for my horrible experiments!