Variety: David Westin has moved from being the person who had the ultimate behind-the-scenes say over “Good Morning America” on ABC to one of the people in front of the camera for an important morning effort from Bloomberg. Westin, the former president of ABC News, will work with Bloomberg anchor Stephanie Ruhle to deliver “Bloomberg <GO>,” a new morning program that the business-news giant hopes will make a splash beyond its time slot.