Regen is a really weak proactive mitigation, which is the whole point of PLD. Stoneskin is a good spell, but does very litte when the situation is already risky. Having Clemency covering both healing and mitigation could be really powerful.
On a sidenote, I'd make the barrier from Clemency stack with Galvanize by being the same status as Divine Veil (Thus, not stacking with Divine Veil). Again, it could offer powerful GCD mitigation...but that's not a problem. PLD is supposed to do that, and keep in mind that Clemency still uses a GCD and interrupts combo, reducing your own DPS...but allowing others to do more damage (MT staying out of tank stance, a DPS able to eat an AoE to stay at close range, etc...)
Hell, I still think Block could be a GCD action without any real balance issue...
