Yeah, I'm doing a bit of catch-up after missing the whole of fall 2012.
3. Mizutani Shizuku (Tonari no Kaibutsu-kun)
With a shortage of potential candidates, Shizuku became the last pick for the season. I would actually prefer Hex from Jormungand for being such a compelling villain, but she's non-existent on the net. Oh well.
But Shizuku's no lightweight, despite her size. Not only she has a tremendous amount of grit for a shoujo heroine, she actually managed to tame the biggest asshole on the block. And... made him fall in love with her. That beats your average loli tsundere any day.
2. Takanashi Rikka (Chuunibyou demo Koi ga Shitai!)
I would be mad if I left Rikka out won't I? Characters often got dumbed down by unrealistic moé attributes and actions, but Rikka had the perfect excuse to act like a complete moron all the time. Seriously, being the original (labeled) Chuunibyou, I don't think it's ever possible to to find someone that oozes more moé than her anymore (not even Tamako). No, it's not possible to watch this and not get a moé overload. She's literally more than the entire K-ON brigade combined.
1. Furugoori Kona, aka Frau Bow (Robotic;Notes)
But even Rikka couldn't beat Kona-chan in terms of uniqueness. Despite the waste Robotic;Notes turned out to be, Kona-chan turns out to be, hands down, the most unique character I've seen so far. Eccentric, genius, hilarious, and she completely broke the norms of bishoujo appeal. She's worlds apart from the lead Aki who had literally zero sex appeal, even without a cute face or any chest to speak of.