im afraid that leavers/afkers and trolls will have even bigger impact than on dominion than on SR, and Riot wants to add ranked mode for it eh.
QQ more please, the trolls are going to part of the gaming community for the rest of your life. Get used to it and remember that while it is indeed happening to you - you've played games against them for free rating too. Think ranked Dominion is a bad idea? Don't play it.