These are some changes to tanks (mostly DRK and PLD) that I thought would be interesting.
(Edited 12/25)
DRK:
Dark Passenger:
Dark Dance effect: Blind
Dark Arts effect: 250 potency
Sole Survivor:
If cast on a party member, everytime the party member takes damage a small portion of the caster's MP will be restored (less than Blood Price). Effect lasts for 30 seconds.