Problem is, that most people, when they see a player parsing very low, are not even trying to help. they simply begin with insults, or straight kicking player out of group, instead of trying to communicate, telling to look up rotation at a certain website, etc.
i had a firsthand experience in ESO, where they officially allows addons and even have personal parcers in game. I've experienced so much rage towards myself, even though i wasn't even highest level yet, it wasn't a high end duty, and it is a first damn week i even play this game, because these nice people compared numbers and began laughing at me.
i am more for a grading system. such will be challenging to implement though, so let's just keep to Sss and forget about whole parcer thing