Maybe there are some hints about the next location in the dragon hold storyline? Since Solstheim was still largely not colonized in the second era it could be cool to be sent their into an unknown wildland to explore it.which gives you much more that adventurer and elder scrolls feeling Solstheim contains a lot of new creatures that are at the same time variants of existing creatures so it would mean less effort on zos side to design completely new things Solstheim has the right size for an expansion and was already a location in 2 other elder scrolls games
the new life festival includes a Skaal (Nord) armor / weapon set besides, i think they will time a Breton/Redguard chapter before / around the release of Elder Scrolls 6 which would make sense for marketing We just had a warm / deserty climate with Elsweyr so i think the next one is gonna be different
