Ro is a special case. Apparently they wanted to feature Ro on DS9 (and then on Voyager) but the actress didn't want to commit, so instead we got Kira (one of the best female characters in Berman Trek) and Torres (one of the worst)
My main issue with Torres is that they gave her an absolutely amazing potential development arc (to grow from "scary and dangerous loose cannon" to "emotionally centered and valuable team member who has accepted herself for who she is"). Then, they had her cover half of it in ONE FRICKIN' EPISODE! And so then, she spends seven seasons on the endless treadmill of "having trouble accepting her Klingon side".Oh, interesting. First time I’m seeing someone saying she’s the worst. What makes you say that? Although not necessarily my favorite character from Voyager, I think B’Elanna is a fascinating character, memorably portrayed by a wonderful actress. It probably helps that she reminds me of women I know in real life. I think if I had to deal with Torres in real life, she’s be a proper pain in the ass, but that doesn’t make her a bad character.
I don't see her as one of the worst characters... but only because Harry was deliberately and calculatedly allowed zero development (instead being artificially locked in as a wet behind the ears ensign when it no longer made sense), Neelix's tremendous potential as a gamma quadrant alien and genocide survivor was also ignored, and Chakotay was based on insights provided by a charlatan. And she is admittedly one of my least favorites.