I'll add my post now
Well my Main is a PLD and I do agree that Stone skin is the best Cross skill for PLD. As I find it handy to cast for many reasons.
1. helps Healers preserve their MP.
2. Reduce the amount of damage I take thus less healing the healers need to do so more MP saved!
3. Good to cast on MT if your OT espcialyl in T5 when you see DS comming up. might even save that Tanks life.
Bloodbath, what I do with that is combine it in a macro with Fight or Flight to boost the effectivness of Bloodbath and they do have the same CD.
Fracture is good when you can't currently hit the enemy but it dose do very little damage.
The only thing better then Stone Skin is foresight, it just the same as Ramparts but with a longer CD.