A question - is it only government civics that help? For example, playing today, I noticed that barbarism doesn't appear to carry any stability penalties (nor vassalage or bureaucracy, for that matter) on the legal civics, with the top two tiers (nationhood and free speech) carry a small bonus.
Labor is the one that confuses me the most - Tribalism, the basic civic, shows no benefit or penalties, but slavery, serfdom, and caste system all show penalties in increased instability - meaning, if I read correctly, that if I move out of tribalism to any other form of legal civic (except emancipation, which comes very late) I will actually make my empire MORE unstable - is this intended this way? I do understand how these civics (slavery in particular) would lead to instability, but it lead to my last game me staying in Tribalism for fear of stability issues...
I guess the question, basically, is does Tribalism also carry an instability penalty of some sort, or is your empire really more stable under Tribalism than any other labor civic prior to emancipation?