Hope you have a nice holiday. I would like to read your Janeway resume please. And it better be good.
Back from my holiday.
Well, let's see. Not trying to be complete here, of course, or neutral, just trying to do the same for Janeway as I did for Sisko in my previous post.
Very soon after attaining her very first post as a ship's Captain (*), Janeway gets to face a challenge so extreme that few, if anyone, in Starfleet can claim to have faced and braved a similar challenge, which consists of being thrown deep into the hostile Delta Quadrant, and being entirely cut off from Starfleet for several years without due preparation. During this time, she gets to redefine the meaning of 'deep space mission'.
During these years, Janeway has to not only be the ship's Captain, with all the responsibilities that come with it (such as leading in combat, being responsible for resource allocation and keeping the ship in one piece and in top shape-- the fact that Voyager usually looks sparkling new attests to her effective leadership in this regard), but she's also more than any other captain in Starfleet responsible for forging a community from the people on board. This is especially important as they ultimately have no-one to rely on, no-one to support them, but themselves. Moreover, this task is complicated further by the fact that there are two groups (not even counting aliens picked up along the way such as Neelix), not particularly friendly to one another, that have to be blended into one seamless crew. At times, she has to maintain a precarious balance between all her different duties.
And she succeeds. Magnificently.
Whereas in the first few years, emphasis is on survival mainly, in later years Janeway and her crew, having gotten very adept at surviving, get to do bigger things. For example, there are the 8472. Initially overpowering the Borg, and threatening to purge the galaxy, and after that initial conflict is won thanks to Janeway's interference, threatening to specifically attack the Federation and earth. Janeway manages to avert the second threat too (at least, we can assume so since we hear little from the 8472's after her 'peace proposal'). Janeway also gets to 'deal a crippling blow to the Borg' in destroying the transwarp hub while getting her crew home at the same time. So she has rid (for the time being, at least) the Federation of at least
two extremely dangerous enemies.
What's more, during all these years, she gets to sow some seeds in the Delta Quadrant about what Federation ideals are all about that may prove crucial in centuries to come. She's sure to have made the impression that perhaps peaceful cooperation and sharing of resources are more fruitful than war and chaos on at least some individuals and cultures along her way home. Seven matures from a drone into an individual under her influence. Neelix changes under her inspired leadership in these years from a self-interested and cynical individual into a person that will act as a true Federation ambassador to the Delta Quadrant. The culture in 'dreadnought' probably won't forget she was willing to sacrifice herself for them. A lot of other cultures (such as the 'night' aliens, and all the cultures of the peoples freed in 'displaced', for example) will remember her with gratitude, too. Such worlds may be more favourably disposed towards the Federation in any future encounters. Some of the 'mini-Federation' members in 'the void' that manage to escape the anomaly probably will spread the word of Federation ideals as well. There are even some con artists trying -and succeeding!- to sell Federation memberships, which -even with the false promises they make- is probably saying something significant about the charisma and the stature the real Janeway holds as a 'federation ambassador' herself in these regions of space.
Everything taken together, Janeway clearly served 'far above and beyond the call of duty', which probably is what got her her well-deserved promotion.
(*) I'm actually not entirely certain about this. Is this established in Voyager explicitly, that Voyager is her first captaincy?