All-In is a special weapon skill from using 2-handed weapons and it does not deal the damage it meant to be.

Some testing:
• 2 AP normal attack: 74 (1st attempt) and 93 damage (2nd attempt)
• Double that: 148 (1st) and 186 (2nd)
• 3 AP All-In: 85 (1st) and 105 (2nd) when it should be around 111~140.

Simply fixing the damage would work but i do have another idea in mind:

Pommel Strike (2AP) with 3 turns cooldown, causing Dizzy which -20% accuracy so the potential of missing the attack is still there but not as serve as Blind status.
Damage scale with levels not with weapon (similar to Tentacle Lash) which it also means not crit-able.
Additional-effect (optional): movement speed is decreased only a little as the victim lose balance, he can't walk really well. Keeping the opponent engaged , if he decide to disengage he won't be moving really far.

Warriors are supposed to keep enemy in line after all so this skill fits well into thier kit.