"60 Minutes" has lost correspondents Cecilia Vega, Scott Pelley, and Sharyn Alfonsi in recent weeks. Taylor Hill/WireImage; Frazer Harrison/WireImage; Marla Aufmuth/Getty Images for Texas Conference for Women Top CBS News editor Bari Weiss is making her mark on "60 Minutes." CBS News has dropped three correspondents in the last week. Those departing correspondents have each described clashes or deep disagreements with CBS News leadership about the network's direction. "The collapse of values at the top has become untenable," fired correspondent Scott Pelley said in a statement Tuesday. "The leadership of 60 Minutes is no longer recognizable. The principles I hold dear are gone, and so I must leave as well." Longtime contributor Anderson Cooper recently stepped down as well. CBS also let go of "60 Minutes" executive producer Tanya Simon and executive editor Draggan Mihailovich last week.…