[b_tterc_p]

I've played with it a few times. It seems like they have you choose features in the space in the order of base -> palette -> art style (loosely) -> pose, but have locked some emotion controlling vector to be happy. Probably a reasonable step for their audience.

[meruru]

I think a large majority of anime art have happy expressions, so it might not have been anything that they had to do.

Edit: "disgusted anime girl that looks at you like you're trash" is the theme of a recent book that got adapted into anime, so it's a bit of a fad currently. I thought that was worth mentioning.