18/1/12 Jhin on ARAM doesn't get a S
Ok so this is part me complaining/blowing off steam, which I do apologize for ahead of time, and part actually posing 2 serious questions. I just played an ARAM where I went 18/1/12 as Jhin. By any and all accounts it was a phenomenal game, better results than I've seen an Jhin put up on ARAM, but the match only got an A+...
That seems ridiculous that anyone can do that well on ARAM and NOT get at least a S. Other games I've played where I've gone barely positive with Taric, Nautilus, Thresh (I'm a sup main btw), Zyra, Kayle, and Zed has gotten me great scores. I understand that these champs are harder to succeed with on ARAM so a good game goes a long way, but it seems incredible to me that any champ with a 18/1/12 record wouldn't get a S.
Since this is weird to me, I have to ask, what exactly is the criteria for getting a S on ARAM? With wards not available and healing being reduced, it feels like damage, KDA, and objectives participation are the only ways to evaluate it.
Another question I have is, since extreme data is accounted for in evaluating a player and assuming there's no flaw in the evaluation system, should there be a regular reset of the system to flush extreme data from the system and keep the evaluation standards accurate to the median skill level of players?