I will say right now - I believe with a much happier team pulling in the same direction and a move back to an offense that stresses player and ball movement, we will see a big rebound year for Jayson Tatum. I believe him to be most affected by the bad chemistry and the iso-ball offense we endured this season.
Also believe we will continue to see the recovery of Gordon Hayward. He will benefit greatly from more ball movement. He will be a consistent contributor this season, but will not return to Utah form until next year, 3 full seasons from the injury and just in time to help the Celts move back into title contention.
Everyone keeps saying Boston will take a step back next season - A step back to what ?? 40+ wins and 4th/5th seed in the East ? So, in reality, not a step back at all, but with a younger team that plays together and will carefully look to add the pieces needed to win banners.