M. Bison is scheduled to be added to Street Fighter 6 on June 26, 2024. This information is based on the web search context provided, which mentions the release date in multiple instances.
The upcoming M. Bison update for Street Fighter 6 hints at a couple of unannounced user interface changes1. These changes include improvements to the Drive Gauge and health bars. When a player is in burnout, the Drive Gauge now has a darker gray gradient occupying the space inside the bar where the meter hasn't been refilled yet. This change makes it easier for players and spectators to see how much meter a player in burnout still needs to recover before they're out of burnout. Additionally, health bars undergo a change specifically when Critical Art is locked and loaded. In the M. Bison update, when a player is stocked with Critical Art, their health bar now emits a glow. This change makes it easier for everyone to see when a Critical Art is stocked, allowing users to quickly glance at the health bar for this information.
Based on the information available, it is not explicitly mentioned if the M. Bison update in Street Fighter 6 will include balance changes. However, the update is confirmed to bring new improvements to the game, such as unannounced UI changes involving health bars and the Drive Meter. While it is possible that balance changes may be included in the update, there is no direct confirmation at this time.