A summary of healer issues

[Deceptus]

Except, it's ogcd, and therefore

1) Mana efficient
2) Does not replace damage output

Stoneskin, on the other hand, if we're being SLIGHTLY honest, was a thing you did at the start of a fight, then forgot existed for the most part and watched while it got cleared by the first thing every boss does, specifically because they were designed to clear stoneskin as their first move.

If you had played at 2.0 you'd know that Stoneskin could be slotted in your extra skills. I used it all the time on PLD as mitigation when the cast time was less than the mechanic cast time. Or at the end of a pull, getting ready for the next group to give my healers some extra breathing room.

Also, it was a flat % so you could put it on FATE mobs to give a HUGE shield (the FF13 event comes to mind, Lightning had a LOT of HP)

As a scholar I used stoneskin a lot in dungeons in battle. I would drop cleric stance, heal the tank, add adloquium and stoneskin, then go back into cleric stance. Stoneskin maybe wasn't the most efficient way, but it was safer and gave extra time between healing. But it's long enough ago that I'm not sure how much I might've needed to heal and how often. I think it was tough for white mage to use stoneskin in battle because of the MP cost, but scholar could manage very well with aetherflow and energy drain. But maybe your idea is also mixed in with that stoneskin II could only be used outside battle (I think?)

Pretty much this. As a SCH in dungeons I would end every pull with an Adlo -> Stoneskin and that gave me plenty of time to set up a Bane Bomb.