Have we had any word from the developers what "Vicky's idea of what a state is" actually is?
You saw the screenshots and the diaries. It cannot handle a state that is not organized along the formal lines of a European state, which means, in practical gameplay terms, things like ability to systematically collect tariffs, establish a uniform income tax (or some functional equivalent), maintain an education system, regular armed forces, political parties (even countries like Russia are getting pretty awkward here!), press laws, social welfare, etc. and, finally, necessarily and inevitably progress towards a bright 20th century future because of the way the technology tree works.
Unfortunately, some states do have to be included and modeled awkwardly with this system (how do you model Confucian China? Oh, let's fudge the numbers of bureaucrats and aristocrats and let the aristocrats work as bureaucrats in absolute monarchies...), but it also means that this should be avoided where it adds virtually nothing to gameplay. I don't much care for 40 identically underdeveloped states in Africa. It adds zero to my gameplay experience.
Now, King obliquely alluded to certain specific options available only to uncivilized states, but we are yet to hear anything concrete.