Injury and weakness has always been a big plus for me ^^ I love being cared for by a lover, and occasionally I feel the big brotherly urge to care for someone.
But I've never mixed this with anthro's... when it's a perfect combo :/ A winged character would have hollow bones, and therefore be very fragile, or a scaly wouldn't be able to retain heat, and so a winters romance could be interesting.
There's other situations I'd like to try... just gotta think of them :)