But when the likes of DS9, Babylon 5, The X-Files, and even stuff like Buffy the Vampire Slayer were starting to dabble in long-term story arcs, Voyager's approach just seemed outdated, and I don't think the stories were, for the most part, strong enough to make up for it.
This is dead-on. Also, often the basic premises could have been entirely episodic, and the exciting development was that TV was finally ready to start developing them into a serialized narrative anyway. But there was no baked-in structural reason X Files or Buffy ever had to move beyond monster-of-the-week, they could have done that indefinitely.
So in that context it was even more frustrating that Voyager had a premise that DEMANDED strong serialization, and mostly refused to engage.
It is no coincidence ... until you add Terry Farrell back into that list, who admits herself her acting skills were insufficient when she was hired.
Heh, don't get me started on what all the female castmember issues on these shows reveals! But unlike Beltran/Wang/Montgomery, she got better, so I'd say she was ultimately validated as good casting. Sometimes you're forced to hire someone who's not there yet, with the belief that they have the raw material and they'll get there.