In real life, rebels have a history of being extremely dangerous to neighbouring countries, because the resulting state was vastly more efficient and driven than the preceding state.
France and Russia are the strongest examples of this, they both went from floundering to scaring even powerful alliances.

It sounds a lot more fun for gameplay if a revolution shakes things up for neighbouring empires, by having their new neighbour be much more dangerous.
There could be a factor called "revolutionary spirit" which gives two of these boosts at random:

Some ideas for revolutionary spirit buffs:
Peace and Bread: +20% pop growth, +50% food and consumer goods
Master Plan: +50% science, +30% alloys
5 Year Plans: +20% to *all* production (including science), -10% happiness
Industrialisation: +30% minerals, +50% alloys and consumer goods, -30% food
The Dream: +50% energy, +50% food, +10% happiness
Crackdown: +50% stability, 30% to energy, minerals, and food, -10% pop growth, -20% science
Modern Thinking: +100% science

After 50 years, a rebel country will lose one of their two boosts. After another 50 years, they'll lose their other boost.

This is intended to be extremely overpowered, because in the current state of the mod, there's seemingly no chance of a revolution replacing the original failed state, it's lucky if it gets to hang onto even one system. And even if it did replace the original failed state, it'd simply be another failed state.
I feel like these extremely powerful buffs are absolutely necessary just to make rebels not completely pathetic.