Earth Blue, I see it now. Stone skin does see some use in the higher level end game content.

Also lots of classes have sets to share.

Drk/Pld/War - tank set share
Whm/Sch/Ast - healer set share
Brd/Mch - Physical Ranged DDs set share
Smn/Blm - Caster DDs set share

The Melee are the only ones that failed preschool. Mnk, Drg, and Nin don't know the values of "sharing is caring."