Aikido actually isn't that poor for damage, the only other moves with notably bad damage is Ki Burst. The point of having a move with low damage and a guaranteed weakening effect is diversity. Otherwise Punch Catch will just be another version of SB. It gives people different choices and options, more damage but less of an effect, or less damage but a guaranteed weakening of your enemy.
As much as there is a chance you lose the roll, the same bad luck could run in your favour and cause your opponent to lose their roll for PRCS. People love to blame the combat system and say it's super random, but if it that random the same randomness works in your favour.
As much as there is a chance you lose the roll, the same bad luck could run in your favour and cause your opponent to lose their roll for PRCS. People love to blame the combat system and say it's super random, but if it that random the same randomness works in your favour.