In terms of physical format I think the most you can do is ban problem cards and let players use them on kitchen counter games as they choose, then when a new set comes around keep a note where the breaking points are. MtG does it plenty of times either having underpowered spells for some sets or playing around with what they can do with 2 mana doomblade. Errata is much easier to add to a digital game, the cards just all change and the broken version is just gone, though we all wish the card became playable rather than nerfed to where it's unplayable. It's also a problem to have two different copies of a card circulating, but I guess collectors will have some fun with it. Players getting their favorite card banned is just part of the territory. If a card is too good it must be changed, don't get too attached to a win condition that's above curve because bans and rotations do happen. I do like the idea they're willing to distribute the errata cards, I don't think I've seen that in physical games. Fully agree minor changes are good for an errata while if it's too different or would just break, just slap a ban and invent a new card later.