I believe Riot absolutely just hates supports. Not so much in terms of character creation, but the rewards systems in place. I've had the hardest time getting S or S+ rankings in game because it seems like its just impossible to please the LoL Gods. I thought maybe well I just suck, but I recently took part in a ranked game that shed some light on the issue.
It was a 4v5 from the get go because our Nidalee jungle went DC and didn't come back in until close to 20 minutes in. At the end of the game, when I had 3 kills, 1 death, and 11 assists, she had the same amount of gold as me. Now I know I'm not the best support or player out there, but I feel that I should at least be given some sort of reward for taking part in the whole game as Nidalee was only in for the last 15 minutes. On top of that, I was only given an A grade with that ratio. It is damn near impossible to get level 7 mastery where my main duo adc had already gotten level 7 on Jinx very shortly after the mastery level was available.
I believe that something needs to be done about this and the unsung heroes of Summoners Rift needs some time in the spotlight as well as the other roles.