Voyager had the potential for some very interesting and intense drama, unique plot arcs, great character development and change, but just utterly failed to execute. Despite all this, it's not the worst Trek series out there in my opinion... just the most disappointing. It could have been so much more.
Folks who say this don't realize how constrained the premise actually was.
You -can- have tension between two different groups of people without them resorting to blows. There is a balance between full fledged mutiny and acting like normal Starfleet people with different rank insignia that the show failed to realize. It's just lazy writing more than anything. They chose to stick with what's familiar.
The premise is that a bunch of people on a small, insignificant ship are thrown to the other side of the Galaxy. Even though the same thing happened to Kirk and Picard with both returning home easily, these guys can't (an early sign of incompetence).
The premise says they will never have any support, meaning no one will EVER help them in ANY way because it would violate the premise. Doing so is a betrayal of the premise and unforgivable.
The crew is made up of two groups who are nominally opposed, but really don't have enough in the way of differences for it to have any impact on the show.
Since they are just one tiny insignificant ship with an insignificant crew (no one famous, no "chosen ones", no God-Humans, no Flagship personnel) nothing they do can be of any real importance on the Galaxy or the Delta Quadrant's well-being because doing anything would make them too important for one tiny insignificant ship.
And since they're always moving they can never stay in one place without getting complaints no matter the reasoning, meaning they'll never be able to introduce recurring characters or give their new aliens the time they need to be better developed. And since the crew are all alien to the Delta Quadrant they have no connection to local affairs meaning there's no dramatic potential there either.
Being an insignificant tiny ship also means they can't introduce anyone tough because a tiny insignificant ship can't beat anyone, so the only option is to constantly run away like spineless cowards from everything. See folks being attacked by space pirates? Well too bad, we're too insignificant to do anything so we'll just run off and let innocent people get slaughtered because we're too chicken-sh*t to try anything.
That is the premise of Voyager.