It's not really random punishment, it's challenges. eg, if you use certain dangerous technologies extensively (eg, strong AI, subspace drives) then a strong lat

It's not really random punishment, it's challenges. eg, if you use certain dangerous technologies extensively (eg, strong AI, subspace drives) then a strong late-game enemy may appear at an unpredictable time (eg, rampaging AI bent on killing all races, rampaging fleets from another dimension). I think this actually works well for Stellaris, because of the vassalization dynamics. In most 4X games, if you get defeated then you're dead and may as well quit. In Stellaris you can get defeated, become a vassal of another nation, and later break out to defeat your former masters. Having a powerful late-game enemy appear makes that sort of shakeup much more likely, as the smaller/vassalized empires may be able to pick off systems from the more powerful, but weakened or distracted, empires.