Winner plays again!
Loser has to take a break.
How I think it would look for League:
1. Win a ranked game and you can immediately que for another ranked game.
2. Lose a ranked game and you are temporarily locked out of ranked que.
3. Win a normal draft game and your ranked que will become available.
4. Lose a normal draft game and you are still temporarily locked out of ranked que.
Some interesting aspects:
This system creates clear intentions. You go to ranked and draft for competition. You go to the other modes for casual entertainment. In current League, there is no designated "practice". This results in a mixture of attitudes. Some casual people and some competitive people on the same team. The casuals get annoyed at the "try hards" and the competitive get annoyed at the "bronzes".
This system puts emphasis on winning the game. It also discourages losing the game. It is important to do both. You want to dissuade people from losing on purpose. You also want to reward people for expressing skill.
Trolling can not be completely eradicated. Ranked ques will experience less trolls overall. Trolls naturally lose more games. In order for a troll to continually troll ranked games, they would have to win normal games. This system just created a positive experience for normal games. It also reduced the amount of impact the troll can possibly have on ranked ques by forcing them to win in a different mode first. Less possible chances to troll ranked.
EDIT: You gunna hafta trust me Rito. This is a million times easier than trying to make algorithms to detect intentional feeders.