So is it any consensus regarding German culture split?
And what about Scandinavian culture btw?
No, currently we don´t have a general concensus but a lot of opinions and several different suggestions how to split german and scandinavian.
IMO most of the language maps linked in earlier posts show the distribution of german dialects after WW2 and are pretty useless for us.
That link
http://upload.wikimedia.org/wikipedia/commons/b/bb/Sprachenkarte_Deutschland1880.png
shows the distribution around 1880 so pre-WW1. BUT that should be taken with a large grain of salt too. It not only gives the dutch as part of lower german but makes the scandinavians striped germans just as the walloons are striped french. We could split celtic to breton, celtic, irish and welsh - and in turn merge german, dutch and scandinavian to germanian ^^
And even if we agree on the lingual borders from 1419 to 1820 - a time in which a lot of changes occured -then we still have the problem to decide which country should get what culture.
e.g. Habsburg Austria. Clearly bavarian as Toio for example suggested. Tyrol, Bavaria, Ostmarch --> bavarian.
And according to that OLD distribution map (far pre-FtG)
http://upload.wikimedia.org/wikipedia/commons/4/42/AlthochdeutscheSprachräume962_Box.jpg
"bavarian" would be the bright orange area.
But then - HAB ruled other areas too. Silesia, Sundgau/Breisgau that are located in our Strassburg or Baden province. The german areas in Bohemia. Vorderösterreich that was spread throughout our Würtemberg province. Aargau and Thurgau right in the midst of Switzerland until the Swiss conquered them.
It would be very strange to see spanish have dutch culture (even if only for a while) while seeing Austria not having the culture of Baden/Sudeten/Silesia...
And Silesia was one of the richest provinces of Austria and certainly NOT "bavarian."
So Austria would still need to have not only bavarian but the other german dialect too. So effectively that would mean that for Austria nothing would have changed...At least for the first 300 years of the game until they lose Silesia and could lose "northern german" or "saxon" or whatever Silesia would be. It would only be a deterrent for the minor german states (e.g. Mainz, Hessen) who only would get one of the german cultures - which again is a strange solution if we look atother minors like Lorraine, Savoy or Pommerania who get two very differnt major cultures.
For any outside nation (e.g. France) nothing changes - it´s the same if there is one german culture that FRA does not have or 3.
IMO splitting away a "northern" or coastal german area would be only useful if we can give Denmark access to that culture to rule Schleswig, Holstein, Oldenburg, Bremen and if we balance that by Denmark losing the culture of Sweden in midgame by splitting Scandinavian too if they historically lose Sweden. However it would be easier to turn Holstein scandinavian under danish rule ^^