The OTL outcome of the American East Coast was, of course, a single state - first a British colony, then an independent English-speaking country - over the entire region, covering a massive geographic and economic distance. But how might the economics of the East Coast have differed if the North-South divide were split by two colonial powers? Say, New Netherlands in the north down to Maryland and Virginia/Carolina in the south down to the Florida border. How does this impact the colonial and later independent economies of the region?
Of course, there are important natural features to consider; cotton and tobacco were probably always going to be grown in the Carolinas, and the Appalachian coal fields were always going to be vital. But with the one not shackled to the other, what might we expect from the two states in economic terms going into the nineteenth century?
I think some good discussion on this question might help with colonial-era TL's (not least my own, which I'm considering reviving...), which often result in just this scenario.