By letting her fail, that's how. By creating more serialized stories were she might make big decisions that have long reaching implications, and the next time she is more reluctant. Let her values be challenged and her to decide to stick by them, whatever the cost.Given all the different viewers out there the writers were never going to please us all. Was Janeway an example of a proficient military Captain, was she conventional enough? Careful enough. Could she satisfy that and take more chances? How can you do both? Be buttoned down to survive and still explore, still take risks.
And, to be fair to VOY, it dabbled in this from time to time, but it never felt like it "stuck" in terms of character growth. Which, is why I can enjoy VOY on an episode by episode basis, but the whole "lost ship" overarching story doesn't work for me.
I don't use Kirk as the yardstick, so I would differ in that respect. Kirk, for me, is a good captain and leader, a flawed man who is aware of his flaws, even if he can still make mistakes.I was avoiding mentioning Kirk in case he challenged Janeway in my reckoning. Kirk embodied the spirit of adventure and ability. He commanded respect. Yet with that smirk of his which was still likeable he was at home in the Captains chair. He was the yardstick.
Picard refused promotion and could often be a bit stuck in his ways, which can be a good thing, and can be a bad thing. I think Janeway was kind of similar in that way.
Sisko is an interesting case study because he has a lot of growing pains and personal pain that he is dealing with. I personally sympathize with him more than the rest, and that may be why I tend to enjoy him more on screen.
YMMV.