It seems this has become less about why many Trek fans rank VOY towards the bottom and more about.... something else.
I don't think it's that hard, really:
1. VOY didn't have the epic/dramatic scope pioneered by DS9, which caused many to see it as a regression.
2. VOY did not have the benefit of being the main sci-fi show (or Trek show) around as TNG did, which made it easier to overlook the latter's faults and harder to overlook the former's.
3. There was a little Trek fatigue, which is why the creators had wanted to delay the start of VOY.
4. There *was* some network meddling, as with TOS.
5. Jeri Taylor nixed a lot of stories because she wanted it to be more like TNG.
6. There was a lack of continuity (though I think it's a little exaggerated. It just stands out more because of DS9.)
7. It was trying too hard to appeal to a mass rather than Trek/niche audience, which made it highly episodic and often more comical than was probably necessary.
8. Fans who actually paid close attention (understandably) grew frustrated with the always-pristine condition of Voyager, despite its severance from SF.
9. Character development wasn't a priority. Many say that's what made DS9 compelling, and how Piller explains he helped "rescue" TNG when he joined TNG in season three. He said he didn't know sci-fi but he knew how to write characters. Piller was only around for the first two seasons and was a lame-duck, so he didn't fight hard to get his ideas accepted (so he says).
10. Seven's arrival was rather controversial for a number of reasons. And many were displeased as it gradually became a trio show focusing on Seven, the Doctor, and Janeway.
11. Some stories were rather poor quality.
12. Many things didn't quite make sense, such as how the primitive Kazon followed Voyager for two years (and away from their home territory).
13. The frequency of Borg episodes was controversial. The Borg were highly popular, especially to the casual fan, but some suffered from "Borg fatigue". The Borg were also portrayed differently with vendettas etc.
I say all that while still ranking VOY at or near the top of my favorite Trek shows. Some of its weaknesses I found endearing, such as the comedy, occasional absurdity, (in my view) fun characters, and the excitement of at least pretending they were out there all alone, even if it didn't seem to make much of a difference.
But then again, I like TNG, DS9, and VOY equally well. I'm glad they were different. The light-hearted VOY is, to me, a fun show. If I want compelling drama and cool story arcs, I'll watch DS9. If I want to see the flagship roam around exploring both physical phenomena and moral dilemmas (with a lot of long, moralizing speeches), I'll watch TNG.
I'm glad for their differences. But I *completely* understand why VOY is less popular with many. It could have been a lot different from how it turned out. But it wasn't.
I respect the opinions of those who don't like VOY, but there is one big advantage to it: if I want to have a non-Trekkie watch an episode with me, I'd go with VOY most every time. I have found DS9 is too hard for them to "get", but VOY needs almost no explanation. The non-Trekkies I've had watch VOY say they like it the best. I hope it thus can serve as a catalyst for getting people hooked on Trek. It did it for me at least.
Sorry for the interruption. I know there's debate going back and forth, so please disregard my opinions as necessary.
I don't think it's that hard, really:
1. VOY didn't have the epic/dramatic scope pioneered by DS9, which caused many to see it as a regression.
2. VOY did not have the benefit of being the main sci-fi show (or Trek show) around as TNG did, which made it easier to overlook the latter's faults and harder to overlook the former's.
3. There was a little Trek fatigue, which is why the creators had wanted to delay the start of VOY.
4. There *was* some network meddling, as with TOS.
5. Jeri Taylor nixed a lot of stories because she wanted it to be more like TNG.
6. There was a lack of continuity (though I think it's a little exaggerated. It just stands out more because of DS9.)
7. It was trying too hard to appeal to a mass rather than Trek/niche audience, which made it highly episodic and often more comical than was probably necessary.
8. Fans who actually paid close attention (understandably) grew frustrated with the always-pristine condition of Voyager, despite its severance from SF.
9. Character development wasn't a priority. Many say that's what made DS9 compelling, and how Piller explains he helped "rescue" TNG when he joined TNG in season three. He said he didn't know sci-fi but he knew how to write characters. Piller was only around for the first two seasons and was a lame-duck, so he didn't fight hard to get his ideas accepted (so he says).
10. Seven's arrival was rather controversial for a number of reasons. And many were displeased as it gradually became a trio show focusing on Seven, the Doctor, and Janeway.
11. Some stories were rather poor quality.
12. Many things didn't quite make sense, such as how the primitive Kazon followed Voyager for two years (and away from their home territory).
13. The frequency of Borg episodes was controversial. The Borg were highly popular, especially to the casual fan, but some suffered from "Borg fatigue". The Borg were also portrayed differently with vendettas etc.
I say all that while still ranking VOY at or near the top of my favorite Trek shows. Some of its weaknesses I found endearing, such as the comedy, occasional absurdity, (in my view) fun characters, and the excitement of at least pretending they were out there all alone, even if it didn't seem to make much of a difference.
But then again, I like TNG, DS9, and VOY equally well. I'm glad they were different. The light-hearted VOY is, to me, a fun show. If I want compelling drama and cool story arcs, I'll watch DS9. If I want to see the flagship roam around exploring both physical phenomena and moral dilemmas (with a lot of long, moralizing speeches), I'll watch TNG.
I'm glad for their differences. But I *completely* understand why VOY is less popular with many. It could have been a lot different from how it turned out. But it wasn't.
I respect the opinions of those who don't like VOY, but there is one big advantage to it: if I want to have a non-Trekkie watch an episode with me, I'd go with VOY most every time. I have found DS9 is too hard for them to "get", but VOY needs almost no explanation. The non-Trekkies I've had watch VOY say they like it the best. I hope it thus can serve as a catalyst for getting people hooked on Trek. It did it for me at least.

Sorry for the interruption. I know there's debate going back and forth, so please disregard my opinions as necessary.