That's because it's the equivalent of a smash echo character. The Avengers team adopted this as one of their methods of releasing new characters last year with the release of Hawkeye and Kate. It's a way to ease the pain of fans waiting so long for content. They're rumored to have one more echo character(potentially She-Hulk) on the way and 2 actually new characters(Winter Soldier and _____) and Winter Soldier is rumored to come with a mini-campaign like Hawkeye.So they bring Jane Foster.....and decide to make her a Thor clone?
Shes could have been such an interesting character if they used her Valkyrie form.....they could even lock her weapon in its flail form and she would be more interesting than a Thor skin.
Tl;dr this is an echo character(since they take less time to develop) so no Valkyrie for now.