League of Legends Ranked Play is BROKEN!

Ok, League of Legends has one MASSIVE flaw that if not addressed, is undoubtedly going to cause the loss of many players. The problem lies in ranked gameplay. I've played over 500 ranked games and easily half of them go like this: I'll take top lane with a champ I'm familiar with and start wrecking my opponent early on in the game starting 3/0 and dominating my lane. Then it happens, "An Ally Has Been Slain", "An Ally Has Been Slain" , "An Ally Has Been Slain". Our Mid lane loses their lane, Our Bot lane loses their lane, our Jungler doesn't know what to do. I'll be 5/0 and start roaming trying to help the other lanes but by this point, its too late. The enemy is too fed for me to do anything about it. This exact scenario happens in most of the ranked games I play. I don't deserve the loss and the loss of LP that follows, as ive done my part to win the game, but my random teammates haven't and I have to pay for it. This gets SO old and SO frustrating that im thinking of quitting the game for good. Riot please, find a way to keep players who don't belong in ranked play OUT OF RANKED PLAY! One Idea I came up with, is putting everyone on a 20 game ranked trial period, if they cant come out with a positive k/d/a average over the 20 game trial period they get locked out of ranked and can try again next season when they are better players. SIMPLE FIX!! THIS WOULD DO WONDERS FOR THE GAME!!!!