I posted this in the general forum, since it would not just impact Blue Mage significantly but has the possibility to inflect negative results on a party. No comments from the general forum though.
I had been thinking about this type of ability for 3 reasons:
1) When I first got Bomb Toss, I wondered if I could 'fumble' it like a Goblin and damage myself
2) The Blue Mage story line and the danger of allowing yourself to be consumed by your abilities
3) I like the concept of great power with the possibility of grave consequences for using that power
At level 99, I'd like to see BLU gain an ability called "Unleash." It would be a timed ability, perhaps 2 minutes in length, perhaps using the 2 hour timer for Azure Lore, where the player looses complete control of the character, not unlike Charm, and transforms into a Psychflayer, including how the player appears. All spells that have been learned by that BLU become accessible to the, what now has essentially become, NPC, and will be used randomly against enemies. The weighted possibility of spell use will be on offensive, high level spells which will also get a significant damage boost. The player will also get a boost against enfeeblements and will become untargetable by any PC until all enemies which have hate on the BLU are defeated or the BLU is defeated. After all current enemies are defeated, if they are defeated, the player will become targetable to PC's and will attack anyone who is, or was, in the party when the transformation took place as well as any non-party PC who acts upon him. At the end of the ability, the BLU would drop to the ground as if he had been defeated, if PC's have not already defeated him. Also, if the BLU is not in a party, any items or gil that would have dropped to a PC will not be dropped by defeated monsters. So, if a party wanted to use this ability as a strategy against a monster, they would essentially need to take a risk themselves by staying in a party with the BLU to obtain drops.
Anyway, just an idea that I think would add more dimension to the job and also fits into the storyline.