I'm someone who vehemently hates that status effect, but I do think it's reasonable from an in-game perspective. It certainly makes sense to me that if you lose your eye then it's going to be a while before you can relearn the skill to really hit vital points. You might still be able to hit them by accident, but making that work in game would probably be complicated. I wonder how viable it would be for them to implement something where, if you crit in battle, you have to do another dice roll to confirm your crit, thus making it less likely?