Viking means pirate. It was an insult the Anglo-Saxon Britons used to refer to them because of all their raids. When they learned they came from the legendary island of Skanda, they also called them Norsmen.
But this term become popular, even for the same Scandinavian people who refer to the “Viking period” of their own countries.
I remember there were two threads discussing whether the name Viking was appropriate or not. They were certainly popular at the time.
1) Keep it name the Vikings, for marketing/promotional purposes
2) Please don’t call them “vikings”
I also recall that there were certain points of consensus among the people:
1) Viking barbaric civilization If the civilization was going to be about the Viking period, including the era of Ragnar Lochbrok, the Danelaw, the berserkers, Norse religion, and its transition to Christian kingdoms, but without going too far beyond 1100, they could very well be called Vikings, or Danish, or Nordic.
2) Scandinavian Kingdoms with Little Vikings
If the civilization was only going to cover the Viking period in the first and second ages, but by the third they’ve completely forgotten about the Viking period and now have landmarks and stone structures, castles, and nothing Viking about them—just stone landmarks and firearms in Imperial Age—they could very well be called “Denmark,” “Norwegian,” or “Sweden.”
It seems they chose the design of the Scandinavian civilization with a full Viking period. In that respect, the name is fine.
Why not Norses or Norsesen?
I would have also liked “Norse,” but I suppose that also clashes with other types of peoples who live in the Northern Hemisphere, like the Rus, Finns, Scots, and others… especially since the Scots lived even further north than the Vikings, and appears in the same DLC.