"I don't believe McNally has written any good plays."
As often I do, I agree with you! The one-two-three punch of seeing Mothers & Sons, It's Only a Play, and Lips Together, Teeth Apart within a year solidified this for me.
He's one of America's most prolific mediocre playwrights. I find most his plays, even his most successful, have a sort of toothless, preaching-to-the-choir self-indulgence.
He does slightly better with his contributions as a bookw riter for shows, if only because of the constraints.
"...everyone finally shut up, and the audience could enjoy the beginning of the Anatevka Pogram in peace."