Is the definition of an Admiral`s job really to first of all stay in one place, usually a desk on a starbase?
Often, yes. In general, it is
not an admiral's job to serve aboard a starship, except when commanding a specific mission.
Voyager is, tautologically, a series about the starship
Voyager. Having Janeway come along on every single mission
Voyager got assigned would've gotten ridiculously contrived, and after a while people would be complaining about it and saying we should've had the guts to kill Janeway off instead of reducing her to such corniness.
No matter what decision was made, people would find things to complain about. That's because every option in life has its positives and negatives. There is no perfect choice. There are only choices. And once a choice has been made, there's really little point in dwelling on it and second-guessing it over and over again.
I don`t get the logic that Voyager has to be a ship-based show. Yes, of course the starship Voyager should be part of it but first of all, the series was about the people on board, not the hardware.
Voyager isn't the hardware, it's the setting. It's the scenario that defines it as a distinct series, just as
Deep Space Nine is the setting that defines that show. If you're going to continue publishing a series called
Voyager, then that has to be its primary setting. If you want to break up the characters and explore their separate lives in other contexts, then that's the end of the series entitled
Voyager; you'd just be dividing the characters up among various series, as was done with Janeway and Seven in TNG and Tuvok in TTN.
And when we did that, people were complaining about how the VGR characters were being used in other series rather than in VGR stories. All you're doing is proving that there is absolutely
nothing we can do in Trek fiction that won't spark complaints and "Aww, why couldn't you have done this instead?" posts from now till doomsday. The answer to "why didn't you do that?" ultimately boils down to "because we did this." One way or another, you have to make a choice, and then you have to make the best of it. No point looking back. Asking whether a choice should have been made differently is the wrong question. The right question is, what do you do
next to make the best of the situation you've chosen?