Even if Riot manages a 50 50 solo to premades win ratio, it won't fix the issue that comes with it
As a solo, beating a premade of less skilled individuals isn't satisfying and losing to a premade of less skilled individuals makes you feel cheated. I imagine the feeling is the same for premades when they also win/lose under these circumstances. These scenarios are necessary for that 50 50 ratio riot wants but it only help for their statistics not the meaningless feeling that these games can cause.