Though game mechanics that aren't hardcoded prevent Stardock and developers from making substantive expansions and DLC when the community can easily do just the same. I support em' too.
I know Mega Events are meant to do foundation-rattling effects upon what would be a "stable" scenario, but I'm just asking for what I think is better for them, and the overall games balance and fluidity is that they take time to fully reach their mass when triggered.
If there was a Mega Event that killed 3/5's of the galaxies population, every single planet, I'm cool with that - till I realize next turn I instantly incurred this whoop-de-do. Mega Events would have so much more substance to them if they could possess dynamic that allowed players and A.I.'s to manipulate and exploit them, and even reduce the severity of their effects upon their own civilization, or region, or even galactic-wide.
What if this Mega Event called "Galactic Bubonic Plague" like every other MG, in ten turns from the start of its activation, naturally raised the severity of its penalties or strength of its effect by 10% every turn, till it hit 100%, than lasted normally like it would, for another 10-50 turns as Mega Event's do, or permanently like the Jagged Knife one.
Now, what if the Yor decided to invest all their incredible researching power into the Event-exclusive technology "Vaccine" that completely negated the MG from affecting that civilization any longer. It takes them 5 turns to accomplish it, and because of such, out of the eligible population of theirs to mathematically drop-off, only 50% did. They're probably now at this point the only civilization to have the most population due to this miraculous save-throw, and they own the least amount of planets too.
But also, due to the total sixth civilizations in the galaxy present, four of them diverted their technology research to the Vaccine, and regardless of whether they completed it in time or not to avert their eligible pop from being lost, they collectively provided bonuses to everyone that researched it. Since 4 out of 6 partook in their own survival, the Yor instead of just saving 50%, ended up having the research cost reduced, and saving more of everyone's population by around 16.7%. I such with math, I know.