the problem with the stun is that it have a less-than 100% chance of working, and it's not each hit possibly triggering the stun, it'd the whole attack. So often I've been unlucky enough to have not stunned the enemy during the entire time the boost lasted. And since it's a 1-turn stun, you either try to keep the enemy stunned for 5 turn (keeping you from other skills) or stun as long as you think it's fit and go for another skill.
IMO, Archivist should have a shield or a blind, with a cooldown that does NOT carry over, so at least you can start the fights with some time to burn those cooldown turns in safety. I think a good revamp would be:
Make all the Right side not carrying over, the left side have their power and cooldown increased, so you have 7 skills to use anytime and 7 boost skills to use when you think it's the perfect time. The right side are basic things like shield and blind, maybe another multi with decent damage, either way, something that gives a basic survival while the left side is cooling down.