Blitz is useful because you can Vault from that stance, which is the only way to get a particular scene outcome from Orc and Demon King encounters.Currently mage is worse than ever. It actually was nerfed by introducing resistances to elements. And it was also nerfed years ago when Hypnosis and Paralysis became shorter in effect then they were.
For mage to be useful, one at least needs to remove the Incantation>Deep Incantation>spell chain, because it's incredible trouble for a little benefit. Spells already are being limited with the mana. Plus they're not that powerful at current meta to be worth all the trouble. They have requirements in Magic that basically force you to invest all the stats in it, so only the mage (nerfed character) will even bother using 95% of spells ever, so what's the point in them requiring Deep Incantation as another penalty. It's such an overkill.
But frankly all the stances should be available from Balanced somehow. Because in my 2+ years of playing I didn't find any use for Blitz or Berserk stances etc. They have pretty weak skills that are not that much more damaging, but actually have lower defense than Offensive skills usually while having higher stability cost. It's already far from top tier, and if it also makes you waste turns to enter their stance (while your enemy is beating you up), it's just useless.
Granted, it's a _losing_ outcome, but it's also the only way to see it and it's pretty fucking hot