Hate is a strong word. It'd take a lot to get me to say I hate a fictional character; they'd have to absolute ruin the show and have no redeemable qualities whatsoever.
In regards to Ashi, my main issue with her is that Season 5 didn't really need her. Sure, you could say "Well Jack needs someone to help him get back from the brink of despair," and that's true. Jack is at a low point he's never been to before. At the same time, Jack has also met any number of characters over the course of several seasons that could potentially return to help him get his mind back on track. What about the girl who he got the robot slug tusks for? Or Momotaro? Honestly, I think if 30 years had passed rather than 50, it would have been much easier for a character from Jack's past to replace Ashi without much issue and it could have stayed a solo journey just like how it started.
There's also the fact that a lot of focus is going to Ashi and her past. We've seen how she was born, raised, the cruelty she went through due to her mother (which is further expanded upon in additional flashbacks and hallucinations), her change from 'evil' to good, her learning more about the world, her learning more about Jack, etc. And that's a serviceable character story, but it feels very flat.
Most of the people in Ashi's past aren't even characters; they're just props that exist to further the story. If I can use an example from /a/, it reminds me of Danganronpa 3 where all of the Future Foundation characters were just there to get killed off and being pointless just so the writer could tell another story with the surviving casts of the first two (technically three) games without needing to actually have anything bad happen to them. And that same kind of thing is here.
Three of Ashi’s sisters have names listed in the credits of Episode 3, but good luck trying to figure out who is whom. None of them matter; their lives were just as bad as Ashi’s, but no one thinks about them.