There's a chat log out there with Ronald Moore (maybe IGN?) where he more or less describes the management styles of the writing on each of the franchises since he worked on TNG, DS9 and VOY. On TNG it was still a new endeavor so they had situations like where he was given basically a free hand to recreate Klingon culture from scratch, on DS9 they were always kinda the red-headed stepchild and generally ignored or left alone to the point where Berman (I think) wanted the Dominion War to be over in like four episodes but didn't care enough that they were allowed to do it for three years.
On Voyager though everything was top-down controlled, they couldn't do this, they had to use that, conflict amongst the crew wasn't allowed (even though one of the original core premises was the conflict between the Maquis and Starfleet), the ship had to be repaired and people had to live so it wasn't too depressing (another part of the original premise being how alone they were), etc. People would come in with good story ideas that Berman and Taylor would instantly kill in favor of crap like Threshold. Story lines and character development were curtailed because higher ups disliked serialization and arcs afraid people just tuning in would be scared off. It being the "flagship" show of UPN just made this all worse and drew in more higher ups with their own ideas of how it should be.
And since Voyager was getting all that focus, DS9 was allowed to even more go down its own path.
There's like a short version of this in Enterprise in the first two seasons (look Ferengi! Borg! Decontamination chamber!) where it was supposed to be this hot new streamlined way to bring in not only new fans who never saw Star Trek before or were afraid of sci-fi, but also to bring back all the Star Trek fans who supposedly loved the TOS and some TNG but bailed due to DS9 and "franchise fatigue." And then they basically stopped caring about it when it failed, Star Trek was added to the title, the third season is one long serial and then you have the fan service final season.