Unless you only look at PvP, at most, you could say that 2 specs are truly worthless and they're both Scoundrel. For PvP, you'll always have FotM builds/specs/etc and there is load more to balance between them so you'll always end up with "worthless" classes, not because they actually *are* worthless but because they're not the absolutely optimal.
This is equivalent to saying that worthless classes in PvP aren't worthless because someday they won't be worthless. Merc Arsenal, Merc Pyro, PT AP, Mara Annihiliation - there's a reason no one uses these classes anymore in competitive ranked PvP. They are all Pareto inefficient. There are other classes that do everything they do at the same or better efficiency. It is a huge hole in class balance. And claiming it is just a temporary phenomenon (i.e "FotM") flies in the face of the fact that some of those classes have been worthless in PvP for a full YEAR.