If your argument is for more diverse body types, I get that. I think you're right in that Malifaux female masters are all young attractive women, with the exception of Ophelia and Zoraida. And Molly/Kirai (dead=no). Someone will correct me if I'm wrong, I'm sure. They very well could have done her as an older, middle aged woman, or made her face look more weathered.
That said, I think they made the right choice making her a small, petite person. And I'll tell you why.
Size matters, but not that way
The "bigger=better" perception is also problem in professional wrestling. Bigger guys can hurt more and take more hits, so all guys should look like that. But here's the thing: assuming that's true, so what? Why is that interesting? Wouldn't you be more impressed, more interested in, a smaller person who takes a hit and keeps going out of sheer force of will?
What's more interesting: a kevlar vest stopping a bullet, or a pocket Constitution? It's the book; kevlar was just doing what it was physically capable of doing. No big deal.
Joss may be big enough to take a punch without flinching, but that ability wouldn't define him. His physical ability to take a hit doesn't say anything about him as a character. It just says "oh, he's big." The reason Ironsides's "take a punch and keep going" characterization works for Ironsides is precisely because she looks too small to do so. Fighting spirit is only noteworthy for underdogs, because it's tough to fight when you're small. Unlike Rocky, this game doesn't have the benefit of 30 minute exposition to show Ironsides as an underdog in her day-to-day existence. We only have visual shorthand, so I think she needed to be small for her "fighting spirit" characterization to work.
Marcus's size works because he's characterized as a man of the wild, like Tarzan. Von Schill is an old vet.
Big burly woman not necessary to fight
Diversity in body types would be nice, but it's not necessary that she be a big burly beast of a woman. Most female fighters aren't. Ronda Rousey, the most famous female fighter in the world, isn't a big burly woman. Her muscles are larger, true. But I don't think she needs to be unattractive or look like a man to take a punch. I'm not a woman nor do I know anything about feminism, but I think there is some middle ground to be had there (where someone can be powerful, but without surrendering their femininity and just becoming a man).
They really went far in the opposite direction of what you wanted. But I don't think it's "another" of the same kind of female master than before. She's short (judging from the hammer), black, very short curly hair (distinctly African-American), not large breasts. What I hope the creators were going for was Snoop from HBO's "The Wire." They have similar job descriptions.
