Every single time I get a premade group on my team, the game is an instant loss. They go into their own little premade world and completely ignore the players not grouped with them. You could be fighting right next to them, they will just keep farming and watch you die. I want the ability to exclude premades from my team. I shouldn't be forced to group with them. They obviously don't want to play with me so why should I be forced to play on their team.
Solo queue should be solo queue. Duo cucks should be moved to flex.
Not all premades are like this, and as a regular premade player I am sorry that you have to regularly encounter this. But, chances are, if someone does something in a premade it's highly likely that they'd do it on their own. Unless they're choosing a champ they're bad at so their premade can carry them (for a mastery chest) in hopes the premade gets an S. In that scenario all you can do is ask them to try their best.
