Lutri, the Spellchaser
We hate the idea of banning a card prior to release. We gave serious consideration to announcing that the card would almost certainly be banned with Core 2021 and letting it be legal rather than break our stance that all cards should be given a chance.
The argument that finally won the day was that not everyone would see that announcement. Many people would buy a legal
Lutri, the Spellchaser as it goes alongside every deck with red and blue in it. Knowing that it would certainly be banned, we were uncomfortable setting up those folks, who are in many ways our primary audience, for far greater disappointment. Better to bend our stance.
This is where we say that it was a one-time thing and we don't expect it to happen again, but that might not be entirely accurate. Wizards is free to explore weird spaces, and, as demonstrated here, those spaces may occasionally do something really problematic. If another card comes along that also does something novel that is incompatible with the format, we'll ban it immediately. Note that “stupidly powerful” is not novel; those cards will get their chance to prove themselves.
Flash
Speaking of exceptional decisions, we are banning
Flash (the card, not the mechanic). Enough cEDH players who we trust have convinced us that it is the only change they need for the environment they seek to cultivate. Though they represent a small fraction of the Commander playerbase, we are willing to make this effort for them. It should not be taken as a signal that we are considering any kind of change in how we intend to manage the format; this is an extraordinary step, and one we are unlikely to repeat.
We use the banlist to guide players in how to approach the format and hope
Flash's role on the list will be to signal “cheating things into play quickly in non-interactive ways isn't interesting, don't do that.”
We believe Commander is still best as a social-focused format and will not be making any changes to accommodate tournament play. Taking responsibility for your and your opponents' fun, including setting expectations with your group, is a fundamental part of the Commander philosophy. Organizers who want to move towards more untrusted games should consider adding additional rules or guidance to create the Commander experience they want to offer.