The MMA’s New American Wing is a feast of paintings. There are so many, and they are so fine and varied, and worth seeing for different reasons. The overall effect is to give a sense of the strength of the American painting tradition, placing it on a par with the European traditions. That’s clearly what the designers of the new wing intended, and they succeeded. And why, evidently, the galleries are “a contemporary interpretation of 19th-century Beaux-Arts galleries,” according to a Museum description. The general sense is familiar great. It engenders a sense of pride in the accomplishments of American painting in the circumscribed period the Wing covers, from the 18th Century to 1920.