Soho Rep has been playing its imminent departure from the downtown black box fondly known as Walkerspace very cool. Yes, the venue is tiny; it lacks disabled access; it’s got water damage and old plumbing and too little electricity to run the AC during tech rehearsals. And yes, Soho Rep’s leadership team, as well as the folks at Playwrights Horizons—where the Rep is about to bunk up for at least two years—are genuinely excited about their upcoming partnership....