I don't think that is the main thing EU series is about so I wouldn't care for it. Sure it would be cool but I prefer better colonization systems and this exciting trade stuff ![Big Grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Venice here i come![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Venice here i come
Let's put this to bed early. There will be no Victoria 2 POP system in EU4. The Victoria 2 POP database is huge undertaking to create in an era when countires did censuses, it is even harder when you don't have these. A POP database is also CPU intensive to use and a lot of work to code (increasing the odds of slow downs and bugs). So we would really need a pretty amazing reason to use one in EU4. We haven't thought up with one so we are not going to do it.
There was similar feature in CK1.I'd quite like a strata system, where the population of a province is just divided into groups - like rich-middle-poor, and these groups can have separate revolt risk and taxes etc. I wouldn't want to see a giant population management thing going on in EU, tho.
I wouldn't want to see POPs, but pie-charts would be nice. Probably not worth the time it would take away from other features though.