Just saw this post from a while back, sorry it took so long to respond. So, AI personalities are something I have planned for implementation "someday" but I think you're under selling the difficulty a bit. It's not "hard" to make an AI personality that requires a certain government but getting it to work can be very tedious. I found this out when I added a personality for a government type that pretends to be a hive mind. All I had to do copy the existing hive mind personality and give it different requirements. But AI personality governs diplomatic responses. For what I was trying to do, it was just a matter of copying the diplo responses that exist, but it gave me a real sense of just how much work creating one from scratch is. There are a lot of responses I'd have to write. And this is just the flavor text. Actual behavior requires looking at the weights of how an AI personality is defined and understanding them and that's conceptual work I haven't done yet.

Besides that, though, I don't know that I fully agree with the premise of your suggestion, that government types should have their own personalities so that (for example) Syndicalists don't go to war. In the first place, this is seems to be working as designed according to how personalities work in the base game. An AI empire's personality usually isn't based on its government. Rather, it's based on, in order of frequency: ethos, founding species traits (probably a holdover from the pre-civics days), civics, and authority or election type. This makes sense in as much as AI personalities are reflections of underling empire attributes. Governments are also reflections of empire attributes in as much as they come from a combination of ethos, authority, and civics. Government type is a flavoring of underlying choices, it doesn't determine anything. So it should be possible for empires with the same government to be hostile to each other if their values beyond those that determine government type are in conflict.

To take the example of Syndicalists: the Syndicalism government requires nothing but that an empire have the Corporate Dominion and Workers' Councils civics. The former requires Oligarchic authority and no amount of Xenophobia ethos. The later requires Egalitarian ethos and no Business Lobby civic. So what we know about Syndicalist empires is that they: have Oligarchic elections, aren't Xenophobes, value Egalitarianism, and aren't infested with business lobbyists. In terms of what this says about personality, it means their high-level decision making is somewhat removed from direct popular control, they are tolerant, and they value equality and are against big business. That leaves a lot unsaid. It's possible for one to value diplomatic ties and peaceful conflict resolution and another to value martial glory and conquest and for such empires to be in conflict despite having some things in common. Arguably, the bigger issue is that the government type itself isn't a coherent reflection of values we associate with Syndicalism. (In truth, I've never been fully happy with how this government type is implemented...)

If I wanted to address this, I'd probably instead create AI personalities for the different kinds of socialist governments. The goal would be for Syndicalists to share that personality type with various other vaguely "good guy" socialists (i.e., the more democratic and permissive ones) as opposed to the "bad guy" socialists (the ones more like stereotypical repressive authoritarian states). To make this, I'd look at what all the "goody" socialist governments have in common (things like certain civics and a lack of Authoritarian ethos) and strongly weight empires with those commonalities towards this personality type.

I do agree, though, that AI personalities would add a lot to this mod. It's just work I have to put on the back burner given all the other stuff I want to do, and on top of that the huge patch coming out soon.

Is this mod still active? Looks like I was a lot worse at spelling 3 years ago than now, hopefully that's changed. I just redownloaded Stellaris for the first time in ages and I see this mod is still updated, which is nice because I like all the new government types and I feel like it adds a lot of immersion.

It's active-ish. My life became a lot more hectic and my plans for the mod a lot more grandiose since the majority of the content was first created. But it's not abandoned or anything.

You will probably be happy to know btw that while I am still not able to implement new personalities, a future update will add triggered opinion modifiers that should make the capitalists and socialists play nice/naughty with each other as appropriate.