Haven't yet ran into this event, but with the many additions of both More Event Mod and Dynamic Political Events , there are already so many that i guess rare events will have a harder time to get a spot.
On other subject, probably got the most disapointing Crisis so far because i played with enabling 1 Fallen Empire in my map and wow it made the Crisis a non-event.
around 2400 the Fallen Empire decide to wake up as we had reached the triggers. It offered me to join them as subjects but even when i declined they did nothing more, just had their recently spawned out of thin air huge fleets floating around a couple of its systems.
2410 finally the Crisis happened, it was the "Unbidden" one. This time the crisis happened in a different empire (last time it was directly in mine) so i felt much less urgency.
Problem : i noticed that the AI despite the 3.3 improvement is really crap at dealing with Crisis. As it's the 2nd time i got to this point and the AI still does not fight back, it's unfortunately not a fluke but a deficiency of the game AI.
While in a normal war the 3.3 AI not only can now put up a fight but has its AI allies even trying to support and fight back, when it's a Crisis it's like the AI does not even notice it's there, the empire that got invaded was simply letting itself get destroyed progressively (didn't noticed any of its fleet moving to defend his own worlds), none of the AI allies was doing anything (it was in a Federation with another AI empire).
Now that is for the normal AI, i witnessed that the fallen empire AI is very different as it's like its fleets were actually triggered by the arrival of the Crisis, i observed that all the Fallen AI fleets were immediately making a beeline to the Crisis center and were annihilating any Unbidden ships on their way.
The balance seems also be thrown off, as at that point the Fallen Empire "simple" fleets were noticably stronger than the Unbidden ones, and i even saw a "merged" fleet of the Fallen Empire that had fire power near to 3 times ! the fire power of the strongest Unbidden fleet.
Strongest Unbidden fleet that would have needed all my fleets (and probably a couple of allies) to match in firepower at that point.
I had to use my fleets jump drive (and wait the 200 days to get the fleets back at full power) to get ahead of the Fallen Empire so i was be able to at least destroy 2 Unbidden "minor" fleets before the Fallen Empire destroyed them all by just sneezing, so i could at least improve my final score.
At least the Unbidden relic is fun, ability to jump all other the small galaxy instead of only 1/3 of it and being faster on the starlanes is cool.
Too bad without DLC the Federation system is so stripped down that any ridiculously small empire can veto any declaration of war because changing the voting system is DLC-only
But wow, playing with Fallen Empires enabled makes really Crisis a joke, will not enable one on my next game.