The comics story could have been really cheap, but it was honestly WONDERFUL. It ran for four years, and it was kind of devastating when it ended. I very rarely think this, but I would have been fine for Jane to continue as Thor for a long, long time.
It would have meant recasting Jane. They pulled off a major recast once, but I don't know if they could manage it again, especially when they're much deeper into their story. Plus, maybe Brie can give Natalie some Jeep-pushing pointers.