I've completed the story several times. Allow me to elaborate on that!
Ash is annoying to some (including me) because of she being extraordinarily needy and clingy. Not only that, but she does some... questionable things to put it mildly (for example, when she pulls a knife on Maria) that would pretty much get her ejected from most reasonable settings realistically. Some of us get really annoyed at a clingy, needy psycho who seemingly has minimal if any consequences for all of her negative traits.
That being said, her personality does reform to an extent, and removing her would necessitate the rewriting of extraordinarily large amounts in other story lines as well, not to mention it is addressed that her behaviour is out of line at times (like the knife situation is addressed), so I'd rather keep and ignore her.
TL;DR is that Ash has a personality that clashes poorly with some players. And this could be said for every other character. (If I begin to rant about Autumn I'll burst a blood vessel, she is a very well written religious person, and I fucking hate religion, so it's a me problem, not a criticism.)