Xbox President Sarah Bond, long thought to be Phil Spencer's heir, is leaving; Xbox Game Studios head Matt Booty is promoted to Chief Content Officer (Ryan McCaffrey/IGN)

Ryan McCaffrey / IGN: Xbox President Sarah Bond, long thought to be Phil Spencer's heir, is leaving; Xbox Game Studios head Matt Booty is promoted to Chief Content Officer   —  Spencer's run with Xbox ends just months shy of the brand's 25th anniversary.  —  Microsoft Gaming CEO Phil Spencer …