For example, you could imagine bracket one has cards that easily can go in any deck, like Swords to Plowshares , Grave Titan , and Cultivate , ...
Swords to Plowshares, which is currently banned from Historic and will probably never be printed into Standard again, is in the lowest power bracket? Am I misunderstanding the purpose of these brackets?
I know one-for-one removal isn't as good in Commander as it is in two-player formats, but even so. Adding Swords or Grave Titan would noticeably raise the power level of every Commander deck I've ever built. Apparently my decks are in bracket zero.
Arena could really be better about handling large numbers of triggers and/or tokens. There's no reason why creating 250 tokens needs to be substantially more work than creating 2, and I suspect that the reason why it is is because there's a lot of redundant stuff -- animation, sound effects -- that it could be skipping, but isn't.