awww *puts popcorn down*

Anyway:
- swiftsong... faster movement in combat... would be nice in aoe heavy fights or in dodge heavy fights(imagine titan or levi or even shiva) - not usable in combat
- hide - not usable it combat(it works on trash because there you don't aggro until you actually use a skill - which is probably what you are seeing - it forces you out of it during boss battles)
- stoneskin II - not usable in combat

So 3 combat jobs as you say have one skill that isn't usable in combat. It's not the end of the world.