I've noticed that during the late game one of the biggest challenges is managing the unhappiness of your settlements as your tax rate increases. While I know that the increasing difficulty of managing your colonists' happiness and the increasing tax rate is designed to motivate you to prepare for a revolution, in some games I feel overwhelmed by all of my cities beginning to riot before I can even summon the resources to deal with it. Just last game I had to accept the tax increases up to 24% because the alternative would've been the "Kalona Gold Party" or the "Numnutz Silver Party". Losing the ability to trade either of those resources would have crippled me just as much as the increasing unhappiness did. Now this wasn't my best game, but I was essentially trapped as all of my cities were in constant revolt and couldn't produce any goods or build anything, ergo I couldn't sell anything and didn't have money to rush happiness buildings. One idea I have to give the player a little more breathing room in this situation is implementing a gallows (or guillotine for the French) building that would maybe give the passive effect of increasing the time between riots at the tradeoff of slightly less productivity in a settlement? I'm pretty sure there would have to be a slight downside to prevent abuse, but anything that keeps my colonists from rioting every other turn would help a lot.