Also if this was to be implemented, the stability boost should have a cap so you can't get infinite stability from moving capitals all the time.
I think catacau was suggesting that, rather than having the new palace bonus
affect stability, the bonus should be
based on stability.
Low military stability = "bonus to army or royal guard" (free unit? free promotion for units fortified at new capital? free XP for units built at new capital?)
Low expansion stability = free jails in non-core cities
Low economy stability = new capital receives free improvements for all resources (and/or free upgrades for all cottages/hamlets in BFC)
Low domestic stability = one turn without anarchy, to change civics and/or religion
Low diplomatic stability = "diplomatic boost to civs close to the new capital"
I really like most of these ideas, but a) I expect it'd require a
lot of work on Leoreth's part to set up, and b) there are way too many moving parts to explain in a tooltip to players. Also, I'm pretty sure that it is by design that the stability mechanic only has inputs and no outputs -- there are many elements in the game that affect stability, but stability itself only really affects whether your civilization collapses. Turning that system into 'things affect stability
and stability affects things' would be a significant change in the game's design philosophy, so I'm not sure if Leoreth would go for it.