YES DO IT NOW!!!
Make the banlist work in matchmaking so you wont get teamed with people on your banlist. So annoying to come in the same team as someone you banlisted since you have probably banlisted them for a reason. Right now it just says; that person is on your banlist. So useless, make it do something useful atleast.
Will not happen. This is an overdiscussed topic but I'll basicly put it together:
Too much abuse.