Personally I always thought that Jane being the 'favorite' wife was Henry's retroactive take on the woman, after all she DID bear him a son and heir. But during her actual time with him, she was always pushed to the side, expected to be the perfect dutiful and quiet Queen who was never allowed to get involved in Henry's political affairs.
In other words, she had less influence than Catherine Howard wound up having. Though if Jane had lived her stock would have gone up, she could have built on it to begin playing the game.
But taking into consideration her actual life... She only became the favorite after death.
I agree, Jane's death meant that there was no bloom lost off the rose, makes one wonder though: if she'd lived, how much different would her treatment by Henry have been to how he did Katherine and Anne before her. Henry seemed to put his love of the moment on a pedestal, and the minute she "descend, be stone no more" his masculinity was insecure enough that he took umbrage at it (Katherine led an army into battle as regent, was victorious, but was never appointed regent again; Anne, well, she was never regent, but he moved heaven and earth to wed her and bed her (not necessarily in that order), and then decided after everything "nope, not this one, either".)
Also, do you think Jane would've continued to be as cold to the Lady Elizabeth? Lizzie was only brought to court by the Lady Mary's insistence, so I could see that Jane's preference for the one over the other perhaps straining the relationship somewhat? And do you think Jane would be any more effective at seeing Mary married off than Anne was? Or do you think Mary's going to remain single until her father is willing to let her marry?