unfortunately, the NA states were not states. as far as i know, & correct me if i'm wrong, they had no system of taxation, had no currency, had no cities -- they were loose federations of tribes at best. many were in the stone age technologically.
on the other hand, the reason they lost so totally in the competition w/ the europeans had more to do w/ disease (which, as i understand it, reduced their populations by b/tw 90 & 99%) than it had to do w/ technological superiority.
also, certainly the aztecs, the incas, & benin were states in the sense i mean.
i'm uncomfortable w/ the cores system as it is -- it gives a huge advantage to certain states that i think had less to do w/ historical determination & more to do w/ the accidents of history & the perspicacity of their leadership. i feel that a "core" province shld become a core after holding it for a long time (there was active colonization in central europe/france, etc. throughout the early period of the game.) but i'm arguing w/ the whole paradox model here, so there's little point in that.
i feel as if states shld start w/ functioning economies in the beginning unless there are historical reasons otherwise. this may be too much work, however; so i dunno. if it were easily done, i'd just give everyone infra 1 at the beginning & a TC in every province they own. but this is all to say that i agree that all states in the game shld be playable, at least.