I don't find them totally abrasive, although I'm not fond of them. I think the concept of the S9 by itself isn't flawed, but the way it was implemented was. I think in a way they were meant to be a dark mirror to the Undersiders, but their threat level was blown way out of proportion and because of that when they didn't turn out to be as dangerous as they supposedly were it just inspired a lot of apathy around them.
Jack Slash could have worked perfectly well as a counterpoint to Skitter, seemingly mediocre power, strange charisma around them, holding together disparate team mates with very different personalities and managing their abilities to maximize their effect, but in the end we just ended up with Joker lite, and I'm not a fan of the Joker anyway.
Bonesaw and Crawler share the position of my least favorite characters in the entire serial. Crawler was just straight up boring invincible monster, he would have worked better as a roaming near mindless pseudo endbringer. Bonesaw seems to exist entirely as the token creepy child, meant to elicit feelings of disgust and horror, but it ends up falling so flat that I just can't take her seriously.
Shatterbird...complete non entity, she seemed to exist solely to showcase Regents full power as well as tossing him a cheap offensive upgrade which could be taken away at any time.
Cherish was potentially interesting, giving insight into Regent and her own childhood, and could have developed into something really interesting, but nope, turned into an environmental hazard by Bonesaw.
Burnscar, Siberian and Hatchet job are all super boring.
Mannequin to me was the only really interesting member of the S9. And I think he would have been more interesting as a separate entity, rather than working in a group.
Really, I could say the same of most of them, they really suffered from being introduced as part of the same group. The entire cloning thing seems to me to be an attempt to actually try and make the S9 feel like a real world ending threat, but in the end it just feels silly.
So, TL;DR potentially good concept, poor implementation. Really, the worst part of it is that we're going to have to deal with reading about more of the S9 as they become more important in verse.