Chests and Balance

I thought RIOT adjusted the reward system for supports and such. I was qued in yesterday almost every match to spt. Some games were S worthy and Id only get key frags. Just now I went mid Karthus and dominated. 10/0/9 to victory. B+?????? Really????? I led my team even after near tilt from bot lane. I'm almost positive I got a chest with Heimer mid....2/1/2. I think there needs to be more adjustments made to this system and I think we need a voting system for VIP of the match.