Dude, no! I never ever meant any USA, Russia or China in modern context!
Superpower = Great Power in PDS terms. Any Western > Eastern > Muslim tech group nation that manages to escape to New World and settle in Caribbeans will become a Great power in XVII century due to immense tax AND trade income while having really weak CNs and natives at their border.
Great Power is what I meant too. In game, you can build a colonial nation equal to the size of the 13 colonies by 1600, and swap to it, OR simply relocate yourself and settle that territory (sucking up 50% autonomy) by then if you prefer. You can be a great power in under 200 years. Historically, look at the USA formation to great power status, and it's that way. You could look at Brazil for a less dramatic example. Relocating to the new world and over hundreds of years building into one of the preeminent world powers is not ahistorical, and not game-breaking. They even nerfed it (except swapped colonial nations) this last dlc. If the puritans could do it, why not a human player?
You are forming a nation on valuable land with abundant natural resources, and barring a very few remote islands, everything in the game you settle historically had people living there. Some of these places, such as Cuba which I linked, were more densely populated in 1444 than Greece, and certainly far more profitable throughout the game's history than Greece. There's no good historical argument for these productive plantation regions to not be so valuable, and there's no good balance reason either really, since redomiciling to America is less powerful than just conquering your neighbors back home... simply far easier or less complicated is all.
I fail to see how Greek sub-tropical lands are less suitable for life than said Caribbeans or Hungarian plains are worse than Delaware bay provinces. If we talk about estimated population, than don't forget that potential =/= actual tax income in said periods, but even so I fail to see how Athens/Epirius/Caucasus region (with 1-3 BT per province)/Chernihiv/Volhynya/Sofia are less populated than St. Martin island in Caribbeans in 1600's. The same about wealth: it's a relative factor, that depends on peacetime and stability, which directly affect the population. Even if Caribbeans are that rich, most of gold is still concentrated in landlords' hands, not in serfs' and slaves'.
You're still putting far too much emphasis on population! The Lesser Antilles were more profitable than regions like Bulgaria in this time period. They had extremely prosperous sugar plantations. The fact that the wealth was tied up locally is very well represented too! You are getting literally 1/4th of the tax value here that you would from a Balkan province connected by land, 1/2 if you moved your cap to the region. Once again, just because there a ton of people in a region does NOT mean it is rich, wealthy, or potentially so. It is true today and it was just as true back then.
These regions were also not at constant peace and stability. The Caribbean was full piracy, and many of these places were raided. On the other hand, places like Bulgaria and Greece spent most of the period in relative calm and under a reasonably stable empire.
BTW Hungary has really low BT compared to most neighbors.
Hungary is a problem but it is also an exception to the norm; it's BT seems to be reflective of having already been demolished by wars with the Ottomans. I think both sides of this debate would agree it is represented too low. This thread at least is more talking about regions like Athens or Southern Italy, which, while possibly full of human people, were not profitable regions. I firmly hold that Athens should in no way have a higher base tax than Havana; it had a stable overlord and was not the victim of regular warfare yet never amounted to anything exciting in this period. Implying it would have under a Byzantine overlord instead of an Ottoman one, despite never being much of anything when the Eastern Romans DID rule over it, is also preposterous. Athens is not particularly that wealthy in CK2, and it's primary source of wealth even today as the center of Greece is tourism; why should it be special in the game?