Communism: hey that ADDITIONAL TRADE SLOT is not that bad, just import Gems+Silver and you have +$3 eco + a lot more boni than all other Gov choices together
Really, if you want to make the Govs unique, invent some Events that happen during special selected Governments from time to time, depending on that Governments ruling style (Riots and Uprisings in Totalitarian or Dictatorship Governments, strikes and Lobbyism in Capitalism, Corruption and mismanagement in Communism, scandals and assassinations in Monarchy and so on.... Also make the list of Governmental Positions (and their effects) different for every government style. Last but not least, allow a Gov change only once every 7days instead of 3days, with the exception of selecting a Gov out of Anarchy, that should stay 3 days.
Finally, every Governmental change is highly costly, because it involves a LOT of buerocracy, so make every change cost $10 per citizen for all the new paperstuff. That would mean, people would be required to do more than just switch between Monarchy for buying infra, Communism for fighting and Democracy for Collecting. People would need to plan when a Change actually is benefitial and they would need to adjust their Governmental Positions from time to time, depending on the new Government, because a Totalitarian State simply does not allow free speech for example. So, instead of 1 Checklist for the Governmental Positions which are only set 1 time when you create your nation, 10 different Checklists with different questions exist. Skill comes into play a bit more than now (to be honest right now everyone just looks at a starting guide and thats it, forever).
If you ask me, that feature has SO MUCH to give, but it is totally underused, which is why the military aspect of this game is dominating everything. People can hardly play different via politics or ruling their nation, since all guides today cover the best strategies and they are extremely simple to do. So the only difference means war, which is imho wrong. A player SHOULD benefit from clever ruling (internally) his nation. Personal skill should count more.