BlizzardGR, with enough work, anything could be made to work. But the point is, does it fit into the game play?
Look, there's already enough game destroying events in the game. There are eco-terrorist that go around, and destroy planets. This is the same thing as your "nova" event. The only way to stop it is to waste the terrorist. Complete pain in the rump. Spoils the game/fun. Why? Because GalCiv is a strategy game, and too much randomness that changes the power balance destroy the fun of the game.
I've found in the gamma, I can almost guarantee a win just by taking the "Lucky" trait. Why? Because it protects me from "Nova" type events (no bad things ever happen to me), and shifts all those bad events to the AI. Whoopsie. What's the point of playing a thinking game where, at the start of every turn, you roll percentile dice, and if the result is "42", you are declared the winner? That's not strategy. That's the main point against these really big events.
In a game where you may play 20,000 turns, carefully building an empire, pursueing a grand strategy while conducting multiple campaigns of conquest, diplomacy, and cultural intergration, having a random event that completely destroys the game isn't fun. That's why people are so busy tinkling on your backside about this. They don't want the fun killed in their game.
Realistically, if any star on the game map went Nova, that would render all worlds unlivable. No worlds, no more game. You'd need to do that silly think in MoO2 and Birth of Feds, and "fix" the star, or it would be a complete game over. So no migration... just researching like made for a special tech. Not much fun in that is there?
Now, what might be fun is a campaign to prevent a major star from going supernova. You know, a linked set of maps were you are battling the local aliens and trying to find some ancient cursor artifacts or library nodes so that your scientist on the homeworld can ultimately cobble together an Ancient star-rejuvenator and prevent the supernova event for another 50,000 years or so. Would that be epic enough for you? It would for me.