Psychic as the job appears in FINAL FANTASY X-2 feels more like a DPS than a tank, and a blue mage is typically able to do everything. I don't believe either one should be considered for the tank role. If we want a new Disciple of War tank, I'd probably go with FINAL FANTASY III's Viking with a warhammer and shield combo.

I've toyed with the idea of a Disciple of Magic tank before. I don't think a lot of people will like the blink tank idea, though (think Utsusemi from FINAL FANTASY XI on ninja). I do think, however, the time battlemage from FINAL FANTASY XII: The Zodiac Age would probably work. Your weapon would be a crossbow, your armor would be the same heavy armor used by tanks already in the game and your actions would be short-range combos (within 8-10 yalms) and time magicks to speed yourself up and slow enemies down, increasing the time a healer has to get your HP back up. You'd have some ways to do damage over time as well.