Current theories on the forums seems to be that either A) they are lazy or B) they are planning specific tuning for future african and asian expansions. But I do hope some modder get into expanding these features into the rest of the world. One point, IMO, for these autonomous colonial empires is to make for a more interesting endgame.
Also, I hope some modder spam tribes across south america. Got to say I really dislike it when they design as though only north americans play this game. As if things weren't silly enough with the province ratio between north and south americas being the way it is (if anything, its the north that has way too many provincs for the average complexity the game has in the americas). I mean, implementing random south american tribes got to be an amazingly easy thing to do for the amount of content it brings, wether you're playing native or colonizer.
They really need to make asian colonization work right, in EU3 I don't remember the euro AI doing much stuff in Asia/India at all, mainly colonizing some provinces. Not to mention that their starting setup in those places (and even in someparts of Europe) is essentially alternate history, and every halfbit modder in EU3 could make a more historically factual setup. West Africa and Southeast Asia were barf-indulcing. Seriously, Paradox. Not to mention these places would need their own mechanics. China is the worst. How is Ming China in EUIV, btw? I haven't played it yet so I don't know, but in EU3 Ming was either bordering the Ottoman Empire by 1520 or so ridiculously pathetic and penalty-stricken in a effort to stop the former situation, that playing with it was a chore.
Yeah the euro-kwan centrism is ridiculous. Especially when one considers that most of north america was SHIT. BANAL. BORING. temperate climate colonies that were just like Europe, and thus, weren't as desired because the action was in places with gold/silver (Andean Plateau, Mexico, Minas Gerais and Mato Grosso, etc) or in the tropical areas where you had sugar cane, cotton, cocoa, spices, etc. Places like the northern thirteen colonies and Canada were essentially the leftovers of the big meal that were grabbed by the second-fiddle colonizers (English, French, Dutch, Danes) or by nearby big boys when they made good borders for clay (Argentina/Uruguay/Southern Brazil) while the best colonizers (Spanish and the Portuguese) grabbed the best clay at the time, like the andean silver mines, northeastern Brazil, caribbean islands, etc. But then again, EU series continuously fails to show american colonies properly, partly because of the foolish insistence to have 1000 soldiers be the default unit size and no possibility of modding it in that aspect.
Dunno how Paradox's gonna go at it, but one thing I would like them to implement in those native american nomadic tribes is to make them like the Horde provinces in EU3: You can't conquer them as you normally do, you have to colonize them, and guard them or the natives will kill the colony. That would adequately simulate both south and north american natives, except they would have to balance it so you want to keep some tribes friendly for advantages instead of just stomping over them.
Yeah, playing native or colonizer countries just scream AAR potential, imagine playing a bunch of stone-age hunter-gatherers and having to transform those guys into something capable of resisting renaissance Europeans with guns. Federation mechanics and nomadism also help to properly depict things like the Iroquois (who often fought amongst themselves) and the Tamoios Confederation. Hope we also get some alternate colony states mod, because I really don't think USA, Brazil and other countries should ALWAYS pop out in games, especially not at their historical shapes. Seeing, say, divided Brazil or the USA being a bunch of little countries would be nice.