When the most noteworthy thing a character ever did was turning down sex with Seven of Nine, you know the writers had no clue what to do with the poor guy at any point throughout 7 seasons of runtime.
The Doctor went through an amazing character arc, had not a single bad episode centred around him and is easily one of the top 10 characters of ST in general.
Torres had a bit of a bland identity conflict thing going on, but at least there was something and her relationship with Paris was a nice touch to add a human element to the plot. Paris himself had a bit of an arc, nothing spectacular, but servicable. Neelix didn't do much, but he had his moments I think. Tuvok is en par with Spock in terms of iconic Vulcans if you ask me. He doesn't really have an arc, but I don't think he really needs one.
And then you have Chakotay, who is just sort of there on the bridge and Kim, who is so bland, you could cut him from the show and it would not change anything. It's a bit of a shame, I think both guys could have been good in their roles, if the writers had actually given them stuff to do.
Voyager had a unique chance to ask the questions:
"What is more important? To cling to Starfleet ideals, even if it means to lose the ship and crew? Or be more open minded, even if it clashes with the Prime Directive? What is the captain's highest priority? To keep to the rules of Starfleet or to keep her crew alive and safe?"
It's an interesting conflict that would play off of the Starfleet-Marquis dynamic and it could have been personified by Janeway and Chakotay... but as with most aspects of Voyager, it was an interesting idea that was sort of there in the beginning but was dropped within a few episodes of the first season in exchange for the tried, tested and somewhat boring Monster/Anomaly-of-the-week plotlines.