Purpose of Screw:
Make it so the states of the HRE are so divided they are no military threat to Denmark. No Military threat means no conversion to Christianity (at least for a while) and less influence in Norway. The probable effect would be a more violent conversion eventually, but not for awhile.
Purpose of the possible TL:
There were a lot of interesting currents within Norse Paganism that were evolving, regionalisms etc that would be fun to explore. Basically I'd like to give them more time to respond to Christianity. Note I don't see Norse Paganism surviving on the continent. But getting certain ideas declared heresy, incorporated into worship and creating a distinctive Norse Church.