Opt to play in a pool where number of mythics are limited
There is nothing more frustrating, tasteless, and stupid than losing to a deck that has 15 mythic cards when you have 2. It's like playing chess against an opponent with 6 queens. Not to mention that it completely defeats the whole definition of the words "mythic" and "rare" when those cards comprise 75% of a player's deck. The automatic matching system seems to do little to prevent this kind of matchup. I would like to see an option where I can explicitly select to only be matched against players with the same number of mythics (and/or rares) in their deck as I have chosen to put in mine. I've given up on this game otherwise--too many pointless idiotic matches that were over before they even began.