If there's any dislike shown toward her, it's probably due to her being less capable of acting than the other people she worked with on the show. Being famous for nepotistic reasons tends to rub people the wrong way. I can't think of any other explanation, given that most fans don't know her at all
What I know of her personally, she seemed like a wonderful lady, & an exceptionally devoted, caring & patient wife to a man who frankly, didn't deserve it, but who created something I think she truly loved, loved being involved with, & seemed proud to witness
As an actress, she's not good. #1 is so forgettable that the very idea of the position she held onboard went forgotten for over 20 years. Chapel was paper thin even for that era, & Lwaxana was utter hackery imho. Half a Life was maybe the only time she stifled it enough to be part of a quality episode. However, that's saying nothing about her personally
Personally, I imagine she must've been a damn rock. Clearly her husband was cheating, and was notorious for his inappropriateness with female cast members, cast members who she shared a work environment with, no less. She's been a life long champion for the show. She had to have been hopelessly in love with Gene, to tolerate what she did, & since Star Trek was going to demand such a huge potion of her life anyhow, maybe her getting some preferential involvement isn't the worst thing that could've happened. She had a right to make her life what she wanted, even if that meant working herself into something she wasn't ideally qualified for, because she could. I will say that I quite enjoy how they used her for the voice of the computer. There's actually some wonderful stuff she played in that character, and that's not sarcasm