Would it be possible to have a "second best" option if there is one? For example, warlocks have a engineering head and a tailoring chest listed as preraid BiS. If I have only one of those professions or none of them I have no idea what my best items are.
Also extremely random items like Archivist Cape and Drakestone that has to proc "of Shadow Wrath" should have a second best item listed. It could take hundreds of runs before you get the correct one, chances are you'll never get both of these items.
For certain classes you can have items like this blocking you from knowing your BiS item through multiple stages.