There aren’t a ton of shows that’s success depends on the acting quality of one person. True, The Office wouldn’t have been as cringe-worthy without the sad desperation of Steve Carell’s Michael Scott, and Tony Soprano wouldn’t have such an effective anti-hero without the pathos of James Gandolfini, but both of those shows were anchored by dozens of other interesting characters played by talented actors. Several storylines in both shows do not involve their main characters, and are often some of the more effective.
This is not possible with Orphan Black because Tatiana Maslany is the show. Sure, the rest of the cast is good (great in the case of Jordan Gavaris), but ultimately, they’re all satellites to Maslany, waiting around to interact with one of her several characters. Maslany’s characters are clones, something the show doesn’t officially tell you until the end of the second episode, but something everyone can probably guess given the nature of these types of shows. Having one actor play multiple characters could go terribly wrong, as it did with Eliza Dushku in Dollhouse. That was another high concept sci-fi show that depended on the acting skills of one person that ultimately failed because Dushku couldn’t make us care. Ringer, a show that was supposed to herald the return of sci-fi favorite Sarah Michelle Geller, crashed and burned because her twin characters couldn’t maintain the interest of audience turned off by a convoluted plot.