Changes should be expensive but they should also be possible. The fact is that most countries in reality massively change their policies over time, but it usually involves major internal conflict. Things like the Bolshevik Revolution or the French Revolution being represented in-game through this would add some depth to the Civ universe. The Civ 4 anarchy system was hinting at that but it was ultimately just too simplistic and not impactful enough to capture the idea.
If they wanted to go in-depth with the idea, they'd need to add a faction system to the game. Each faction would have things they cared about and when you make changes, you risk angering one of the factions. If you anger a faction enough, you can potentially trigger a rebellion or civil war. From the player perspective, you would usually just avoid angering factions but if you really wanted something badly enough you'd have the option to make the change and deal with the fallout.
Adding this sort of internal conflict to the game could also help combat the problem of the game getting boring once you've snowballed to a superpower. I'm not sure if this is the type of nuance they want in a Civ game, but plenty of strategy games have had something similar so it's not that outlandish IMO.
If they wanted to go in-depth with the idea, they'd need to add a faction system to the game. Each faction would have things they cared about and when you make changes, you risk angering one of the factions. If you anger a faction enough, you can potentially trigger a rebellion or civil war. From the player perspective, you would usually just avoid angering factions but if you really wanted something badly enough you'd have the option to make the change and deal with the fallout.
Adding this sort of internal conflict to the game could also help combat the problem of the game getting boring once you've snowballed to a superpower. I'm not sure if this is the type of nuance they want in a Civ game, but plenty of strategy games have had something similar so it's not that outlandish IMO.