Support grading is NOT working correctly
As a disclaimer, I know that score isn't directly used for rating and it's not a perfect measurement for skill. It does, however, mean something - especially deaths. If you're contributing to fights and not dying, you're probably doing well. I've been working on Nami tier 7 for months now, and been having troubles. The two s' (here and here) were good games, but not much better than my normal - and certainly worse than other games. I was, however, using the "pro build." Usually, I get around the B+ to A- range, even when I'm going 0/4/24, 1/2/16 1/0/7, or even 4/2/37 - which are FANTASTIC for a support. Keeping in mind, I do an extremely healing focused build - to the point where I outheal sorakas that I go against. My healing done is phenominal, though my damage naturally suffers (but, since nami's typically don't build damage anyway, that shouldn't matter.) My winrate with her is also quite good. So, I just did a match and did something completely bonkers. I went full damage. 12/18/0. Ignite and all. Here's the match. I went 7/10/12. Compared to my usual scores, that's absolutely terrible. I haven't gotten that many deaths in almost a month. I was missing q's and going in anyway, diving for no reason, getting caught out... it's a miracle my team carried me through that. And yet... I still got a B+. I'm not a pro player, but I know when I do terribly. Hell, even my damage done was only barely higher than my typcal damage done in similar game lengths. I don't know what you're using to measure a Nami's skill, but it can't be right. Meanwhile, I get S or S+ on about 75% of my Soraka games... I'm certainly a better Soraka, but I've been playing Nami regularly since the day she was released.
TL;DR - My grade is too high for my bad games and too low for my good games.
EDIT: added more links, because backing up your arguments with evidence is good.
EDIT 2: Here's another game. I got S-. I did good, sure, but I didn't do S- good. Whatever it's measuring, it's not performance.
