For almost 25 years Frank Castorf has put on a stridently modern kind of “Regietheater” (director’s theatre) at Berlin’s Volksbühne. After the fall of the Wall, the famously grouchy Castorf persuaded the likes of Christoph Schlingensief and René Pollesch to stage works at the theatre on Rosa-Luxemburg-Platz. They let disenfranchised subjects stumble elegantly through superannuated ideologies, speaking in voices that are not their own. And they won’t be doing it for long. Jan Küveler knows what we’re going to miss.