Alright I have a followup question:
Dead empires (Those empires with super-good technology but an inability to reproduce it, who sound like MMORPG raids where you go and raid them for awesome technology) are actual entities in the game. Because I assume you'd have to declare war on them and use warscore to enforce demands that they'd also have a diplomacy option. Will there be more interactions with them than raiding them for loot? If I'm, for example, an ultra-rich merchant empire can I hire them to fight a war against a military invader against me? Can I ally them? They won't expand on their own, but what are the limits of their interactions with the rest of the game?
If I was crazy enough could I help them rebuild their technology and create the Borg?