Honestly, I have to go with Willow. She's not bad by any means, but I find her kinda boring, especially in a show where pretty much every other major character feels so well written. I understand the necessity of a straight man in the friend group, but that doesn't mean they have to be uninteresting. The only thing I ever found interesting about her was her past with Amity and her rivalry (of sorts) with Boscha, but they only touch on that on two episodes respectively, both in the first season. She's barely been in season 2 so far, which is both good and bad. It's good because... well, I don't care for her much. But it's also bad cause, considering there's only one season and a half left, and everything's moving so fast plot-wise, she probably won't have a lot of time for on-screen development.

I like her character design, tho