Whats up with the instant game autofill?

Can we slow down with the whole matchmaking? If i see a 3 minute Queue time I don't mind waiting for 3 minutes.... to get my main role. Every other time I get a game in 40 seconds but i end up either getting autofilled or just given my second role. It makes it really annoying to climb in my main rank when i keep getting autofilled, then given my secondary, then autofilled again.