Of all the years to add a second theater. With almost twice the stage acreage to fill, no artistic director to help with the filling and some $6 million to lavish on plays carefully calibrated to fill as many seats as possible — while still making theatergoers feel like they’re the smartest, most special people in town — the Kansas City Repertory Theatre has managed to plug amiably on. Tonight’s premiere looks promising: John Patrick Shanley’s Doubt, the smart, audience-pleasing, Pulitzer-snagging drama of faith and race that, if you’ve paid attention, you’ve probably seen at two or three other Kansas City theaters already. At the Rep’s Spencer Theater (4949 Cherry, 816-235-2700), where the stage is old-school and horizon-wide, even the familiar has a habit of taking on new life. It’s not what the Rep does best, but it is what the Rep does most often.