Brawl matchmaking is unfair and I uninstalled the game because of this. Some friends got me thinking about commander again, so I thought I would reinstall Arena and have some fun. Instead it was a few hours of misery, because literally 90% of my opponents had high-pace optimized decks. I could not even come close to competing with my outdated decks. To be clear, I am not trying to hate on the power level of good decks/cards, but rather that the matchmaking is deplorable and it made me quit the game. Since it is not Ranked (by player), perhaps the algorithm needs to quantitatively estimate the deck strength for matchmaking purposes.