It's a bit radical, but not at all dumb or unbalanced.
Truth be told, if you get cursed, the match should belong to him.
It should.
But non Tager people have many tools to avoid every single bug, not only though movement, but through Counter Assaults, bursts, gold bursts, reversals, etc, those which do apply to Tager also.
Sure he can lock you down and hit with either of the two, but it's only a circumstance.
His 12ks are situational just like Hakumen's.
He needs to hit with a jc or a 2c, the curse gauge has to be near full, meaning the attack has to hit when they're first cursed, if he commits to a 2c and it's blocked, he wastes curse meter due to the insane recovery time, on average he'll score roughly 8-9k, trying.
He can go for simpler mixups at the sacrifice of damage of course, which is the often taken route.
As easily as he can score a 12k, it's just as easy to avoid it and thus the possibility of eating 12k, because the longer you last, the lower your chances and the lower the damage if he actually hits you.
It's a two sided guessing game, and over head or a low.
High rewarding (as curse mode should be), but not at all broken.