WAR utilities: IB can be up for pretty much every tank buster in the game, highest OT DPS, Slashing damage buff, flat damage out debuff, unga.

DRK utilities: Best CDs versus magic, worst versus physical. If a monk is in the party, DRK brings nothing else except DPS. It's the only tank punished for using its aggro combo and stacking VIT (Darkside ticks at all times, aggro combo is net MP loss, Living Dead requires max hp worth of heals in 10s)

PLD utilities: Stoneskin/Clemency/Divine Veil, STR debuff, best CDs versus physical, best panic button(HG), better against magic than DRK is versus phys, Cover, stun on the GCD, has a silence.
PLD is basically the "support" tank, like MCH/SMN/BRD are "support" DPS. It undeniably has the best utility of all the 3 tanks. Have you played any of them except DRK for 15 seconds? If you want to hit big(ger) numbers level another tank or play DPS.