Witch Broom Mount from the Halloween Exchange also has a gigantic hit box when you're on the mount on a ladder. Spoiler
Notice my character's name bar and how far it is compared to where a normal mount would be: Spoiler I don't know if that's intentional, but it does ruin the broom mount a little bit.
That sounds right. You wouldn't want your mount to go behind your nameplate. It wouldn't be very appealing.