In a Broadway season that is light on plays, “Richard Greenberg has the opportunity to become the first American writer to have two new plays running simultaneously on Broadway since Neil Simon did it in 1992 with “Jake’s Women” and “Lost in Yonkers.” (The British playwright David Hare did it in 1999 with “Amy’s View” and his one-man show, “Via Dolorosa.”) It is a league, however, that Mr. Greenberg has trouble considering himself a part of.”