devtrackers.gg
Do these become legal in historic brawl?
It will be legal in Brawl, yes
Are there any plans to revamp or at least tweak the Brawl matchmaking in response to all these new cards?
I ask because with the current deluge of powerful cards, and Modern Horizons 3 at the... uhh, horizon, the ability for janky and mid-tier decks to compete is rapidly diminishing. It would be a shame for the format to turn fully competitive when its main strength is its sheer diversity.
We're actively discussing this. The goal for Brawl matchmaking is to let players come in with whatever kind of deck they like (including janky & mid-tier nonsense) and give them a fun and fair match. We have tools we've talked about a bit here for Commanders, and we will continue to monitor how the composition of the 99 are impacting things there.