Hi! Writer himself here.
I can't talk about other writers, but in my case I'm pretty open to any idea on critique about my character. Before submitting any contet I upload the google document to the "Event submission" forum in fenoxo.com for anyone to check and make any suggestion, that includes your own if you want to. In fact, I've taken notice of how some of you guys don't like her introduction and I'm wroking on the *teleporting* thing, seeing if we can make some changes in that aspect (which may take long, since it will first be reviewed and all). So if there's any other suggestion I would be happy to hear about it. Honestly.
Setting that aside you also need to keep in mind that each character is different and so are their dynamics (The "Taur lady" you mention has a gentler personality, is less corrupted and, as you said, her own appearance being dominant allows for a different dynamic). That also applies to the kinks they "treat". Evelyn is a gentle domme, displaying superiority with her high class manners while Lyla content is all about humiliation.
That said, Wsan is one of the best writers this game has (my favorite at least) while english is not my mother tongue and I'm writting for free as a hobby, so yeah my content is not as good as his.
Hey, so just because of this post I decided to go back and play though her content and seriously consider it. (I didn't bother finding a buttplug to continue, I'm not sure how much more is gated behind that.)
If she's so corrupted, then something about that needs to be foreshadowed. Our first encounter is an orderly camp with a woman studiously maintaining her sword and upon first hearing and sight of some one else, she leaps up, crosses how much distance there is between us in the time it takes to glance down and back up again. These are the actions of some one who means business, and isn't particularly fussy if some one's in the wrong place at the wrong time. Also, she kind of jumps from guarded to life story pretty quick. There's no inclination of any kind of interest except for when she looks you up and down at sword point and bites her lip, but that could just as easily be taken for indetermination. And then after a frankly depressing backstory, where she pretty much puts up a wall between you, you immediately ask for sex. It's kind of out of the blue and she laughs at you, but not because your suggestion is ridiculous, it's because "I'm the boss of this gym."
There's no real arousal or chemistry. And frankly, in a world with Kasyrra in it, she's a little plain jane to be expecting us to beg her for the privilege of her affection. You haven't actually established that it's worth anything yet or why we even want it.
I think there are some interesting things you can do to spice up her dynamic. Make her earn her attitude by introducing her as a combat encounter, and let's see how she really stacks up against the main character. Combat for example could reveal alot about her character, she could have unique versions of those dominant special moves, where she tells you about how she's going to humiliate you after the fight if she wins. Atleast you'd have time to pepper hints of her personality in there that make the actual sex less jarring. There are a few good tense first encounters in the game but hers goes a little too far I feel like.
So I think the most constructive criticism I can offer is either take it a little slower to introduce her character and establish why we want her to humiliate us in the first place. A below average (relatively, considering some other characters) penis, isn't really justification enough. At least Eryka has her mood swings, and they're pretty close to the same character. I think something your girl will struggle with is really distinguishing herself, especially as the cast grows. Humiliation is a rough niche, because I can get that by basically loosing any fight.
Either way, good luck in your endeavours!