Lvl 80 and below PLD is really only clemency and divine veil. GNB has Aurora which is pretty weak and not reliable until you get the second charge and HOC. DRK has abyssal drain which is on a 60s cooldown and the only other sustain comes from its invuln and its 123 combo.

WAR has how many moves to heal? Reason I am bringing up lvl 80 and below is because that content still exists and is where healers are needed in those dungeons where a WAR is not there.

GNB and DRK dont really have a button or series of buttons to sustain them like a WAR and PLD do. So we cant really say all tanks. I highly doubt they are going to nerf WAR considering it is the fan favorite, most played tank, and is the most purchased job level skip.