5man preamde vs all random team is the absolute worst experience in League.
i would rather have a toxic team telling me to kill myself then to go up against a 5man premade as a team of all randoms.
This is something that should never ever happen under any circumstances. And yet i'm seeing this happen more and more often. these matches are almost so one-sided in the premade favour, their coordination and communication is far superior then a group of random people who were placed together and almost always the team has a smurf or two in them who's skill far exceeds the elo the rest of the team is in..
When this happens matchmaking sacrifices then fun one of team to enhance the fun of the other and this is something that should never happen in league, ever.
5mans should only ever vs 5mans.