You call it a melee and ranged hybrid with high attack power and low vitality, but it has high evasion and high parry and the ability to heal itself, largely countering its drawback.

It has very strong debilitating effects.

It can restore 100 TP and 18% MP to the party every 2.5 minutes. Compare to Shroud of Saints, which currently restores about 1000 MP, a bit less than 25% (and it's not a %), to the WHM's MP (and nobody else's) every 2 minutes. Also steps on BRD's toes.

It has some powerful abilities with 15 minute and 1 hour recast times. The game is balanced around 5 minute recasts.

It can give Dragoons the ability to play well. That alone breaks the game.