"Viable" in an MMO doesn't mean "it's within the realm of possibility to use this class in an encounter".
It's technically "viable" to run savage with an entire player down, if the rest of the group is insanely-well geared, but you wouldn't do that because it'd be idiocy to not fill up all of the raid slots.
No, "viable" means they compete for raid spots with the other classes of that type, which AST certainly did NOT.
