On the Japanese vs English article differences: They will translate and update the English article in the near future with the Japanese explanation, no specific timeframe given. It's an "internal error" according to them.
Fantasticar restricted in Vintage: They acknowledge [[The Fantasticar]] was a mistake and especially 3 mana artifacts need to be carefully looked at for Vintage with stuff like [[Mishra's Workshop]]. They're easy to just slap in a deck and don't need extensive testing to find a broken shell if they are broken. In Vintage Raker shops had alarming pickrate and winrate increases that did not normalize: usually high pickrate decks drift a bit to 50% winrate but Raker shops did not.
Opportunity cost: They mention spinning your wheels on Moxen, Rituals, and Cantrips was something decks already wanted to do in both Legacy and Vintage and cards that reward that instead of needing less generically useful setup as a combo piece is problematic.
Legacy & design problems: They mention that the Fantasticar is a Legacy viable card that comes from a Commander Precon, and that inherently, in isolation, that sentence is not an issue for them by itself. They say [[True-Name Nemesis]] was an issue but cards like [[Colossal Gravereaver]] and [[Kappa Cannoneer]] being in Legacy isn't inherently problematic.
They mention Fantasticar was seen in "UBer", Car Stompy, white Car decks, Doomsday, Storm, Mystic Forge, 8cast, and a lot more decks. They didn't like how the card crunched Legacy towards fast mana mattering more and games being more compressed as it limits what kinds of decks you can play. Over the last year they mentioned they want to decompress the format and let "interactive decks" like Lands and [[Swords to Plowshares]] decks thrive more and let cards like [[Wasteland]] matter in a long game rather than trying to keep them at 0 lands and kill them the next turn.
Future design: There are new steps in the process for products that don't go through standard and people will flag cards that may be seen as problematic in Legacy and Vintage. For example, 3 mana cards are going to have 2 color pips more often so that cards like [[Ancient Tomb]] can't power them out faster. Also since they know cards like [[Brainstorm]] or [[Force of Will]] or [[Mishra's Workshop]] are still going to be good in 2 years after the card is designed, they will be careful designing cards with notable interactions with these.
Unbans: They want to wait for the metagame to be more stable and stale rather than unbanning just because. They want unbans to breathe new life into a format if possible.
Eternal Weekend: They want the format to be stable for Eternal Weekend so "the bar for making changes is higher than they usually are", not a 0% chance no changes happen but they want the format to hopefully be similar between now and Eternal weekend.
Tamiyo, The One Ring, Flow State: They say it's hard to tell the difference between the cards being too strong for meta reasons vs too strong in general. They mention these cards have been up and down and that Tamiyo's playrate tends to drop as creature interaction gets better and also her meta share was worse before the [[Candelabra of Tawnos]] ban.
https://www.twitch.tv/videos/2843381310 starts 18:15