Broadway got lost in the stars this year. It seemed that everywhere you looked — at least in that consortium of temples, er, theaters around Times Square dedicated to the adoration of the boldface — there was yet another celebrity, using his or her magnetism to draw gullible audiences and, as often as not, upset the balance of a perfectly good drama. It is fitting that the fall’s runaway hit, Terence McNally’s “It’s Only a Play,” was an overextended sketch in which famous people portrayed famous people talking about famous people.