I'd personally like to see more of Yuyuko being badass. I'm sure we all know that her air-head happy go lucky personality is an act... well, sort of. Not that I don't like her like that, because I do, but she really does need to be shown off in a more serious manner sometimes. I rarely see that, and it makes me a sad panda.
Speaking of seeing less of something in a character, I know Momiji doesn't really have a canon personality, but as much as I love seeing her adorable moe-miji persona, I prefer a more serious tengu warrior-like Momiji. After/During Symposium she was given more character, but, eh, that was 50 years ago (in the TH timeline).
I would think of more, and I probably will, but that's about it for now..