I'm not sure we'll be able to bring this discussion further. What I call Mærafylki actually consist of 3 different fylkis. If you want "Raumsdalr" as a fylki you should split out Sunnmærafylki and Norðmærafylki. All three are quite historical and should maybe be there, but then we should have even more regions too of equal importance. In addition to gameplay reasons I have it as one county since Ragnvaldr was named Mærajarl for all 3 counties after Haraldr seized the area.
What would be incorrect is to rename the entire area to "Raumsdalr".
This is also something I'm not going to agree with unless you can send me a link or referance giving another suggestion for name. I trust my own solid sources unless proven otherwise.
I kinda like the idea of a no-mans land as there was indeed "unsettled" or less control in this area, but I don't think it's worth wasting time on making. The region borders are quite clear so I prefer using that and rather have the settlements along the coast as this will make the inland area dark and unknown... unless you make watchtowers of course. It will cause a problem with mercenaries in this area for sure, possibly more problems I wouldn't know about.