I am surprised to see how Scandinavian countries are unpopular.
I think we should always have a Viking nation. Denmark and Norway have few votes, I'm assuming people expect them are rotating with each other. But Sweden? I would particularly love to have the Swedes in every edition of the game.
They all are pretty comparable, sadly. Norway was strongest around the time of Harald Hadrada in the 1000s, spanning Norway, Iceland, Greenland, and (and disputably parts of Britain and Denmark). Denmark was the strongest around the time of Margaret 1 in the 1300s, incorporating the entirety of Scandinavia. And Sweden was strongest under Gustav Adolphus in the 1600s, conquering Finland, part of Norway, and much of the Baltic countries; less territory overall, but it has remained the dominant culture in the area since.
So really, the argument is over preference of time period. Do you want a naval civ that was more relevant in the distant past (Norway, Denmark), or in the present day (Sweden)? Both the vikings and the more modern Scandinavian powers are important, so picking between the two is impossible. And if you exclude that from the equation, how do you choose between three similarly sized empires, just in different centuries?
It's roughly comparable to asking players whether they think the Rashidun, Umayyad, or Fatimid caliphate should be a mainstay. Or the Qin, Jin, or Tang dynasties. Or Frankia, Prussia, and Bohemia. If there's no clear winner, the choice is arbitrary and not worth seriously considering. I mean, is VI honestly better with Sweden over Denmark or Denmark over Sweden, or without either of them? We have a viking civ already, so the majority of consumers' needs are already met.
EDIT: I actually thought of an elegant solution. Norway is ancient civ. Sweden is modern civ. Margaret of Denmark is added as an alternate leader for both civs. Two civs. Three leaders. Perfect balance.