From what I've read, they originate from a collection of self-serving leaders of a wide collection of planets and motivations. Traders, bankers, technologists... all wanting to do their no-entirely-honorable things without Republican laws and restrictions and taxes. Ignoring the Sideous-Dooku deception going on underneath, what's the typical Separatist thinking of it all? Is it a Libertarian movement? Get Big Government out of my life. Is it a matter of seeing the Republic ignoring their needs, so taking matters into their own hands? Or is it just being the helpless subjects of corrupt leaders and not having any say in it at all? I'm pondering this stuff for a story in my head that has a Separatist thinking back to the old days of the War.