The provinces of
Møre and
Rogaland should be added to Norway.
This would split the Norwegian west coast (and what is currently Bergenshus) into three provinces with approximately the same size (
Bergenshus being the third).
The fun part is that none of the new provinces would be too small compared to the provinces around it.
The fact that the entirety of Western Norway can be taken without much effort is just odd, it becomes even weirder when you realise Bergenshus is one of the biggest (if not the biggest) of the scandinavian provinces.
It is bigger than Finnmark, which in the real world is larger than the entirety of today's Denmark.
Adding these provinces would
a) Make it harder to take the Norwegian west coast, which was essential for the Norwegian trade northwards
b) The trade in these provinces would be fish, which would make certain Norway is leading producer even if it loses the islands in the west and båhuslen (which happened historically)

c) Make Norway less of a pushover for Sweden and Denmark and a larger naval power than before, with Denmark and Sweden still being better naval and land powers due to NI
Bergenshus should be the richest of the three provinces.
Also, if possible, make Sognefjorden twice the size. Trying to downplay the second largest fjord in the world tsk tsk

.