And, if in your particular game of Civ, as an example, all major players are already under Democracy and/or Communist Governments by the 1848 turn, the whole thing being a trigger seems pretty cartoonish, wouldn't you agree?
Democracy and Communism, as a glance at current events for the past 75 years or so shows, both have their own internal sources for potential conflict, revolution, civil war, and other unpleasantness. In a properly designed game of Civ, a government with the financial problems the French
Ancien Regime monarchy had in 1789 would be ripe for revolution/civil war. (as would almost any other form of government facing that particular financial crisis, which had been building since at least 1714!)
What the result of that conflict would be should be far, far less predictable. What kind of effect it would have on subsequent developments in that and other countries and governments would likewise be, ideally, much less predictable, being a composite of long term effects related and unrelated to the specific crisis in one specific country, no matter how influential that country was.
If I were to replay the same situation of 1789 multiple times with the same Civs, Leaders, and starting situation I would hope that, due to variations in Great People and sheer Random Factor of millions of people involved, that I would get somewhat different outcomes each time. Any game design that does not account for such 'random factors' in the works isn't worth playing as a game, only as a Simulation Scenario to study some historical event, and would be utterly lacking in the Wonder Factor inherent in a good game where, ideally, one gets different situations develop in each game.
Clausewitz, specifically in a military setting, referred to 'Friction' - the myriad factors that oppose, confuse, distract, or completely gum up the workings of any system, government, culture, or organization. With that replicated in some way, the game is open to variations and is endlessly fascinating. Without it, any game is both Fantasy and also resoundingly Dull: you does A, B follows, C results, every time. Replay Value = Zero.