In the weeks leading up to Pacific Investment Management Co.’s annual forum in May that sets the firm’s long-term investment outlook, Bill Gross was facing internal dissent. At investment committee meetings in April and May, four of his six newly appointed deputy investment chiefs questioned whether their boss, manager of the world’s biggest bond fund and an investing legend, was too pessimistic about the economy. Mark Kiesel, Pimco’s head of corporate bonds, said that the U.S.