A comment on random events - while many people enjoy the replayability they add, others can find this extremely frustrating.
Let's say a player had started a game on max difficulty, with the goal of employing careful planning and diplomacy to pull off a minimal-defense expansion gambit in the early game. Through thorough planning and hours of delicate maneuvering, they manage to gain a bunch of cities with rich resources, and are just starting to convert that territory into a military advantage, when suddenly, an eclipse event hits out of the blue and hordes of monsters appear to destroy all their cities with no warning and no possible response, rendering all of the player's effort moot - and worst of all, the defeat would have nothing to do with the player's skill, since there was no way to anticipate such an event.
Perhaps a way to make these events a replayability-enhancing test of skill rather than a f*** you directed at the player would be to give some sort of advance warning - for instance, 50 turns before the event, you get a message saying "Mystics have seen signs in the sky predicting a time when nature will rise against those who seek to tame it.", then, ten turns before the event, a message says "Astrologers have forseen an imminent eclipse of the sun - when this disaster strikes, monsters will swarm into the realms of men and fallen." The importance of this warning is that it gives the player a chance to plan ahead, and makes failure to adapt the results of player misjudgement rather than just bad luck.