The idea that playwrights shouldn't direct their own work is almost axiomatic; you can see it all over the reviews of John Patrick Shanley's Storefront Church, for instance, and it's such an article of faith for an old hand like Sondheim that he takes pains in Look, I Made a Hat to point out that frequent collaborator James Lapine is the exception that proves the rule. I understand the reasoning--that writers can't be "objective" about their work—and I've certainly seen plenty of shows in which the directorial hand of the writer was insufficiently strong, and it was probably safe to assume that someone outside the writer's own head would have sharpened the proceedings. But I don't quite understand why the writer/director is held up as an ideal in film, the showrunner/creator/producer is similarly elevated in television, but stage autocrats get the stink eye.
I asked the question flatly on the American Theatre Facebook page today ("Should playwrights direct their own work?") and got a fair number of immediate and unqualified "nos" and "nevers," as well as some predictable and healthy pushback. But my favorite response comes courtesy of Robert Garfat of British Columbia:
Canadian playwright, George F. Walker, used to get flak from two particular press critics for directing his own work. One critic said that Walker's plays were great, but Walker was a poor director. The other said that Walker was a fine director, but his plays were no good. Then George discovered a play written by an obscure French playwright and took it to the stage, directing the production, called Theatre of the Film Noir. Both critics loved the production, the first because Walker's direction of this inferior and obscure French work was sublime. The second critic lauded the play, saying that even though Walker's direction wasn't up to its usual standard, this play was much superior to those plays written by Walker. A week later, George revealed that he had written the play under a pseudonym.Check and mate. Nobody knows anything.