The WoW: Forever Podcast: Episode 3 - Dive Into Dungeons With Devs ft. @Hammerdancegaming
Aggrend says a dungeon XP bug is being fixed. Kill XP was based on the highest-level player in the group and will now use your own level. Together with a 20% boost to dungeon kill XP, this should put dungeon leveling close to optimal questing, but Blizzard won't let dungeon cleaving become the best way to 60.