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Will this be what influences them most? Will other factors have an influence? Eg. the money they do/don't have? Money they hope to earn? Available jobs?
I think it'll be an important factor, but I doubt you'll get mass immigration to a province with no jobs even with it (which would be undesireable anyway, you'd end up with loads of unemployed poor people there => MIL problems). A state that's already getting immigration and has plenty of jobs to fill should benefit the most.
I was wondering whether the Americas will still have a hard-coded bonus, and while I hope they don't, they should be able to benefit from lots of immigration (I don't want germans moving to India en masse, if India has good and profitable jobs). Then I realised that with the province traits of climate and terrain, there now exists a tool to steer POPs to emigrate to provinces similar to their homelands. Finns and Swedes would find Michigan and Minnesota etc. more attractive than people from other cultures would, and Spaniards might be more willing to migrate to warmer California and Florida, as well as South and Central America. If this isn't in the release, I'd certainly be interested in modding it in (if promotion logic will be in text files, I don't see why migration logic shouldn't be).
The main thing is that this would guide immigration and the major colonies historically: South America, South Africa, and Australia would attain statehood easier and be more developed, whereas the tropical jungles and deserts would see much much less European immigration, and for India, it'd be easier to encourage a locate bureaucracy than try to get Brits to move there.