I think an excellent example of a massive random event that affects all players (Human/AI) is one that was included in the Fall From Heaven II mod for Civ IV. Can't remember what it was called but it was introduced beautifully, something about all civs struggling to exist and that only hte strong of each civ would survive. Basically all farms,plantations (but not mines or workshops/windmills) were wiped from the map and therefore all large cities suffered a falloff in pop. Very well done, caught me by surprise and loved playing through it. What i'm trying to say is that random events would be cool as long as you *know* that all players will suffer equally from whatever it is.
That is Blight and it's not a random event. It happens whenever the Armageddon Counter hits a certain point (the developer keeps using patches to change the exact number the AC needs to reach.)
Blight is a cool mega-event precisely because it is not random. It has a set requirement, one that you have control over. If you don't want to bother with blight, found ashen veil yourself so you have control over its spread and sit on it, stifle its spread, so that no one adopts it. If a neighbor founds AV and/or builds the prophecy of ragnarok, build an army, kick the shit out of him and raze his cities. If Blight's mechanism were "roll a dice each turn to see if it happens", it would be retarded, even if there were some requirement like "the dice rolling starts at a certain turn".
Here is an example of how not to do mega-events: Sword of the Stars. In that game, at the end of every turn past turn 99, it checks to see if any combat happened that turn. If not, there is a 2% chance for a grand menace - one of 3 incredibly powerful spaceships that goes around glassing planets - to spawn at a random location. Everything is wrong with this mechanic. Let's see:
-The spawning is random unless you go out of your way to pick tiny, meaningless fights every turn.
-They can only hit one civ at a time, except for the locust fleetworld, which can only hit one civ at a time at first but can self-replicate once it's eaten (literally) enough planets.
-The first point at which they can start showing up is at a time when no civ will possibly have anything that can stop them. There's also a chance that they won't spawn till the antimatter era, when civs might have powerful enough toys to pound a grand menace like a midget inmate's asshole. But...
-The tech trees are largely randomized. Maybe 30% of the techs have a 100% chance to show up in any given game. The rest, including all the really mean weapons and tough shields, require a dice roll. These rolls are all made at the beginning of any given game, so no save scumming to circumvent them. As it comes to civs fighting each other this works out fine, since there's a large enough variety of well-balanced weapons, shields and armors that there is pretty much always SOMETHING effective that you can field. However, they aren't well balanced vs. GMs. GMs have very specific counters that are needed to best them, one which no civ is guarenteed to get. (Liir and Morrigi are close to guaranteed, but that makes it all the more infuriating when they fail the appropriate tech roll on a 10% chance or whatever.)
So you have a random chance to smash the living fuck out of 1 or 2 randomly picked civs while all the others kick back and laugh, and how bad the damage is is also heavily RNG based (due to tech rolls and the time of spawn.) Stupid, stupid, stpuid. Here's hoping Elemental stays away from that kind of crap.
