I was just thinking about aliens and different kinds there could be, like Flood-like or Predator-like or even ones like the Na'vi from the movie Avatar.
The idea of a nearly catastrophic parasitic alien filled my brain with al sorts of ideas of their life cycles, emergent behaviors, and viralness. A flood-like organism could decimate entire planets, eventually causing a organization to form that would quarntine that sector. Also a company could weaponize the parasite and conquer worlds. There'd have to be vaccines that have to be researched and discovered too, so that the disease/parasite isn't unstoppable.
Then I thought about races like the Ood and Vortigaunts, which are both slave races. So that got me thinking would DU give you the option to travel to some planet with primitive aliens and using your superior technology you could conquer them and then enslave them. Now of course there would have to be different types of slavery; such as chattel, servant, war drudges, work serfs, and livestock. All of these would have different buffs, but you could just have general slaves that follow your commands. Those buffs would be like, for example: you are attacked by a band of raiders, so you would use war drudges because the other slave types do less damage and are slower fighters than the war drudges. Also you could face rebellions, uprisings, and slave runaways.
I believe all of these would add more emersion, plus some really cool scenarios could arise from it.