The American Shakespeare Theatre in Stratford, Conn.--a bastion for the Bard of Avon for years--is undergoing major changes. Earlier this month, its 18-member board resigned en masse, and this week Gov. William O'Neill's task force recommended that the embattled facility produce plays by other writers too. The recommendations also for reduced seating (down from 1,500 to 800) at a cost of $15.5 million. The festival, which hasn't given a complete summer season since 1982, is under the administration of the state, and the board of directors resigned over a perceived lack of control. Gov. O'Neill has not yet acted on the task force's recommendations.