In order to create a region of continuous hostility and danger – and the ever-present possibility of ferocious violence – I went the classic race/religion route, simply because it reflects real life, and the Solomani flavour of the region, and the Empty Quarter’s namesake.
[I also have a simple metanarrative: ‘the locals are going to have to learn to work together, as endless hatreds and endless war leads to endless poverty.’ The PCs are going to have to figure out how to cajole their corner of the sector into a better future (…and profit from it …and keep down those who would break the budding peace): the basics are there, but nothing is going to change until the first step is made.
Especially as the Imperial Navy is gone for an unknown amount of time, so the PCs will have to provide their own protection.]
However, I have nothing against less intense, lethal, and controversial drivers for violence: and a greater focus on feuding corporations or noble houses (or, to a lesser extent, hostile nations & empires) makes for games with a broader appeal. Classic Battletech has a rich background for such a Referee. It has a free sourcebook here that is well worth skimming, and various House books (search for “Battletech House” on www.rpgnow.com: the old books are cheaper than the recent books) that can give a aristocracy-oriented Referee ideas.