I hate Noike. In my opinion she's a character that did not need to be added to the Tenchi OVA series. I also hate her backstory that has something to do with a female Kagato(another unneeded character).
And as many people have already said, she's too perfect.

I had a weird meta-thought about this while reading through this thread - if I were Noike, I'd probably feel the same way everyone else does about the way I was presented in OAV3.

Noike didn't seem like a bad character to me and she did have some potential to be interesting. However, just shoving her into the story very abruptly and then pretending nothing ever happened was just stupid on the writer's part. Noike never gets a chance to form any relationships (good or bad) with the other characters, so it always seemed to me like Noike was an outsider, a stranger living in the same house rather than a member of the family. So I don't so much hate the character Noike as much as the yoyo's that couldn't bother to do decent job of integrating her into the storyline.

On a different thought, if Noike was intended to be a substitute for (Galaxy Police) Kiyone Makibi, then for goodness sake just put Kiyone in there! Kiyone has been a long established character, has been pretty much liked by most fans of Tenchi Muyo and had her own place in the story that wasn't already occupied by someone else, the "Oh woe is me! Someone put me out of my misery" type person. I guess the fact that Mr. Kajishima didn't create her, meant an automatic exclusion from his universe.