One further note...

…on the technologically advanced civilization vs. WH40K Imperium of Man scenario occasionally played with.

What we might have here is a really dramatic example of why you don’t want single points of failure, regardless of how well defended you think your single points of failure are.

Combine Jon’s Law (any interesting space drive is a weapon of mass destruction) with the Imperium’s centralized governance (not exactly great centralized governance, but something has to provide centripetal force to the whole tangled mess – even if that’s mostly a corpsified and gross symbol these days) and even more centralized navigation system (Astronomican), throw in the way that canonical WH40K assumes that space defenses are porous and blind at medium-to-long range, and what you have a situation that just screams “relativistic kill vehicle“.

Basically, you whack Holy Terra with an RKV, then smirk as the thousands of successor splinter states, reft of their unifying symbol, are only prevented from slashing each other to suicide by their inability to reach each other in any sort of organized fashion. You may not have cured your human problem, but you’ve definitely reduced it to manageability.