>>44840138I believe that it relates to the theme of Opelucid City exclusive versions. Iris is the new generation of trainers, raised in a traditional setting(Opelucid White), who's destined to surpass her predecessors. Since Drayden, her predecessor, is the 8th Gym Leader in BW, then there's no other option for her than to conquer the pokemon league. Drayden is the old generation of trainers who has to adjust to the modern life(Opelucid Black) and let the new kids shine. This is why he's demoted to 7th Gym Leader status in B2W2.
