There is nothing wrong with LBs themselves, aside maybe from RPR (but i hold my judgment on that for now since i havent tested that job yet).

On the case with SAM, it is ONLY considered powerful because most Jobs cant prevent the 100% dmg trough guard from happening, and the few that can, often pay as bad of a attention as the people that get the debuff and keep fighting face-first in the first place, and then wonder why they got their teeth kicked out.