Cover is niche enough as it is, I really just wish it was off the gauge entirely.
We have precedent for gauge abilities having their own cooldowns with current Cover AND DRK's Living Shadow so if we had a strong oGCD offensive option it wouldn't be strange to place it on a cooldown.
It makes no sense why Divine Veil has to be so awkward when no other class has to deal with such a stipulation for BETTER mitigation.
As for Clemency as an oGCD it would be nice considering it is PLD's only self-sustain but I'm not sure what would be the best way to implement it