I see it like this:
1. Jane will be near death, and then War THOR will appear and the ultimate hammer will go to her and thus War Thor reverts to his old self and Jane becomes the new War THOR.
2. Meanwhile, the REAL THOR pulls his head out of his rear, realizes that he has always been worthy given all that he has done over the years, sobers up and goes to reclaim the hammer that is rightfully his.
Remember the Beta Ray Bill mini-series when he was hunting Galactus? Storm Breaker judged him unworthy and he lost his THOR powers and reverted to his original cyborg self. In the end he felt he was unworthy until a revived Korbinnite convinced him he was worthy and he reclaimed the hammer.
I suspect that in the end this has been the whole problem, THOR believes he is unworthy thus he IS unworthy even though he isn't
You know, that sounds pretty rationale on how they could keep both and bring back the REAL Thor. Excellent thinking!