Sciencebox back to 100
Something to make monarchy more interesting. In short: Federation has +5% sci output, communism low corruption (!!), despotism 20 units for martial law, tribalism 4 free units, democracy no bribing/inciting, fundamentalism special units and republic early boost to trade. Monarchy could use something else. For example some small wonder could be built only with monarchy. Some of the wonders we have in the game are related to monarchy, at least in some way. That way we would also have some logic to it. civ2civ3 is designed to make all the governments relevant during the entire game but monarchy has not been that popular because of the pyramids.
Another option would be making pyramids slightly harder to get. It could require some other useful building. In any case whatever change we decide to make it shouldn't be anything that would change the game too much.
check how the fundamentalism/crusaders actually worked in lt37
The changes to terrain. How about this:
Spice would give 3 food instead of 2 (you can't irrigate swamp as you could before)
Iron would give 4 prod instead of 3 (there is no food and iron is really important irl)
Anything else? Something that should have less resources?