If Blue Mage Became A Full Caster DPS Job (Unlikely), Which Spells?

[Gserpent]

Blue Mage rather should be a Tank,
BLU has a Tank Stance
BLU has Invul
BLU's gimmick is to get hit
The Tank Symbol is also Blue.. and looking at Paladin, Holy Spirit, Holy Circle.. if that ain't cast spells!?
It kinda writes itself

A ranged tank would never be allowed in a game like this. This is a game that *rigidly* adheres to the holy trinity in raids.