Eric Mangini's hiring as a senior consultant, ostensibly to help the San Francisco 49ers' offense prepare for opposing defenses, raises obvious questions about longer-term implications. It's reasonable to wonder whether the 49ers have lined up their next defensive coordinator.Vic Fangio has, by all accounts, done a good job in that role. He remains the 49ers' defensive coordinator. He could continue in the role for many years to come.However, Mangini built his reputation as a defensive coach.