Players are recognizing cards that are unbalanced sooner than WotC is implementing effective changes to rebalance the game. Additionally, since we don't have the ability to choose who we are getting matched against we don't have the ability to say "No, I don't want to play with that person" until after the match starts. For example, if I were playing Brawl in person and my opponent was running Ugin, Eye of Storms as their commander, I would tell them to play a different deck or find a different opponent because I'm not going to waste my time.

My proposal is a feature allowing players to select up to three nonland cards that they don't want to encounter. They would then not get matched against any decks running any of their personally selected cards; likewise, if they are running a card that other people don't want to encounter, they wouldn't get matched up against those people either. Players can change their three cards whenever they like (except for during a game), and they are not required to select cards at all if they don't want to. I believe this will help streamline the matchmaking algorithm to ensure people are enjoying more games.

Edit for additional detail: This would not effect matchmaking in ranked or limited, only for casual play.