Megyn Kelly’s decision to jump from Fox News to NBC resolves one of the last unanswered questions of the Roger Ailes scandal: Would she stay or would she go when her contract ended? With her last show set to air on Friday, Kelly’s departure raises a new series of questions about how transferrable her talents are and where Fox News is headed now that the network has lost its biggest star and one of its few hosts with serious mainstream credibility. For Kelly, the jump from a primetime perch at Fox to a multifaceted role at NBC carries a high...