Yes shield oath is stronger than defiance but deliverance is far stronger than sword oath, it simply doesn't make sense for WAR to get a free stance swap with 10 second recast while PLD gets an mp cost to swap stance with double the recast. As for DRK getting a 30 second recast that's not good design at all, no one wants to be STUCK in grit for 30 seconds, look at the amount of complaining cleric stance gets over fat thumbing the button for a FIVE second recast!