The reward adornment from the solo and heroic collections are locked to a specific slot (legs, chest) and are arguably worse then the adornments that most people already use in those slots, however if you allowed those adorns to be used in any slot specifically in the white version they would be arguably BIS for several pieces like cloak, charm, wrist ...etc and would be highly desirably. As the adorns are now, talking to most of my guildees they are not motivated to finish those shiny collections because they feel the rewards are of no value.