Alright, I admit I was being a bit of a dick, but hear me out.
Her overall design is definitely a strong selling point for me, not because I'm particularly fond of petite women, but because it fits well with the narrative. She starts off in the sewers, scrawny as hell, barely able to bludgeon rats to death and only has about one day's worth of food. She turns a corner and there's a shit ton of traps and a dead chick next to a campfire. Fuck, are those goblins? She's screwed! No, wait, she makes it! Possibly with a well earned sword to remember the experience by! As she continue to struggle through an unforgiving and increasingly difficult world, she learns to make the most out of what she has, because she has to. And as she starts getting better and better at it, people start to recognize her efforts. Hell, bandits and monsters even start to run from her at some point.
After a while, you get bored or your save file no longer works, whatever. You start a new game again and remember: She wasn't always a badass. She used to be this fragile looking thing that could barely kill two rats before getting winded.
She could have been a beefy ass amazon or a buxom seductress, but no, she looks like someone that's going to have to go through hell if she doesn't want to starve to death. And that's exactly what this game is about. I feel like it's not really fair to say the game's unplayable because of the way she looks. That's completely missing the point. She's perfectly crafted for the atmosphere the game is going for.