Well there's at least one person who really doesn't like Brad Stevens as the new Head of basketball Operations for the Celtics, and that's Stephen A. Smith. Smith actually makes a fair point that its rather irregular for a coach after a season of struggles to get promoted. That's true. But also the national media was always off on the Stevens story. He was NEVER on the hot seat with Celtics ownership or Ainge. They just signed him to a coaching contract extension last summer.
Stevens is not the first coach to become a general manager or whatever each organization labels their shot caller, so it's not some huge reach for him to be hired for the role.