I’ve only seen a few episodes of Voyager, of which I think only one had Jeri Ryan in it.
In all three, Janeway came across as a bitch. Whatever the writers were trying to accomplish with her character, they needed to stop. Moral quandary? Janeway will order an explicit and wrong resolution, with no particular argument behind it. End of episode. Whee.
All of the rest of the cast were somewhere between bland and annoying. The second in command of the ship would briefly seem human, but even he seemed pretty blah.
7 of 9’s episode was clearly better than the rest. She seemed like a real character and wasn’t unlikable. I couldn’t care less that she was popularly good looking, that’s not my style (Dax, on the other hand, rawr). And, for example, Whoopi Goldberg’s character was (usually) a welcome addition to a TNG episode and she’s not a potential lingerie model (no offense, Whoopi). I’m sure that very few viewers minded the eye candy, but she didn’t make the show in the same way that Jennifer Love Hewitt (supposedly) makes The Ghost Whisperer. She genuinely appears to have been the only good thing on the show, what she looked like withstanding.
And if Mulgrew had an issue with a casting decision, that had nothing to do with the actor brought in for the part. She should have taken it out on the producers, or just been happy to have the show leave the cutting block.
ETA: Whoops, I forgot about the doctor. He was good. If the show had just been the Doc and 7 of 9, it might have been a hit.