It seems Norse is atleast somewhat heavily requested, being 3rd og top 3 voted picks.
So i’d say by popular demand we’ll likely see Norse one day… thou i think Byzantine and Ottoman empire might come out first… unless they decide to proper “expansions” and not just Dlcs so we get scores of civs at once.
For those interested in how far the Norse/Scandinavians expanded, while not “one” large empire… they were found almost all over the European, and mediterranean area, even as far as North America (Vinland).