I concede the latter is true if you concentrate on serialization as being about stories external to the ship. It became pretty ridiculous how Voyager was still dealing with Kazon by the close of Season 2, when they should have traveled through tens of thousands of light years of space.* Considering the Kazon never came across as anything but a minor power, this came across as a bit ridiculous.
That said, Voyager should have been highly serialized internally, in terms of having consistent character arcs and ongoing dynamic character development. Voyager went out of its way, barring a few cases, to ensure that none of the character moments we ever saw would be reflected upon again. So Neelix would have great moments, like his questioning of faith in Mortal Coil, and then go back to being a bumbling fool. Or Torres would become "Born Again" in the Klingon religion in the amazing Barge of the Dead, and then a few seasons later tell the religious Klingons in Lineage she was a non-believer. Or the inconsistent way in which Seven and The Doctor were treated, becoming more or less human as the plot of the week required, rather than having consistent movement forward (or at least, if they regressed, setbacks which made sense from a narrative perspective.
In addition, it would have made sense for Voyager to have constructed a whole supporting cast of recurring characters on the ship beyond the odd ones like Vorik and Samanata Wildman. Given the ship was constantly traveling through space, except in weird cases like Q and Barclay it was hard to have any character not on the ship recur from season to season. But if they had spent some time fleshing out another 20 or so characters, entire stories could have sprung from them from time to time - as long as the show had the confidence to not thin every episode needed a wacky sci-fi premise or alien of the week. Basically, Voyager should have embraced more of the soap opera element of Trek than TNG or DS9 did, because it fits well with the small crew cooped up on a ship together for years aspect.
* Season 2, perhaps not coincidentally, was the one time Voyager really experimented with serialization, with the Kazon arc involving Cullah, Seska, and Micheal Jonas. The arc was honestly horrible, but that had more to do with the Kazon not being believable bad guys and the writing not being great for it than anything. Nonetheless, Voyager's seeming lesson from this was serialization=bad, and they never bothered to do something so ambitious again.