Wizards of the Coast (WotC) dropped a surprise Banned & Restricted announcement today, banning Winota, Joiner of Forces and Expressive Iteration in Pioneer.
Naya Winota has long been the boogeyman of Pioneer as it can be play a normal aggressive game of Magic while also presenting unanswerable board states as early as Turn 3. WotC said the deck is suppressing deck diversity and reducing incentives to play other linear aggressive decks. Due to its high win rate, large metagame share, and frustrating play patterns, Winota, is no longer fit for Pioneer.
Expressive Iteration has made itself known in every format, providing incredible card selection and card advantage to Izzet decks of any flavor. In an attempt to bring the Izzet decks more in line with the rest of the format, WotC is banning the powerful two-mana sorcery while leaving Dig Through Time and Treasure Cruise in the format to give Pioneer a clear identity.
While Winota was already banned in Explorer, the MTG Arena-only format is also banning Expressive Iteration to keep the format aligned with Pioneer. No other formats are being affected and Lotus Field is notably being untouched for another B&R announcement.
Read the official announcement from WotC.