Perspective: How do you make a play about Joan Rivers without Joan Rivers?

“Can we talk?” Joan Rivers’ stand-up tagline had a way of turning audiences into confidants. Goldstein’s background is in musical theater — he won the Kleban Prize for most promising musical theater librettist — and “Joan” is written in the broad, episodic style that musicals enjoy. Goldstein has plenty of consequential actions to choose from, but he slides into a recap of a story that I mostly already knew from interviews and the superb documentary “Joan Rivers: A Piece of Work.” “The Marvelous Mrs. Maisel” and “Hacks” — both of which use Rivers’ life, to varying degrees, as a model for their protagonists — have taken us inside the personal and professional hurdles of being a trailblazing female stand-up comic in the Rivers mode. In trying to tell Rivers’ whole story, “Joan” winds up skimming the surface.