It’s Joss Whedon so you gotta watch. And Whedon warrants that you keep watching. “Dollhouse,” Whedon’s highly-anticipated return to television debuting Feb. 13 on Fox, has some problems but shows plenty of promise. Eliza Dushku stars as Echo, a young woman with a mysterious past who signs on with the Dollhouse, a secret organization that wipes clean the minds of its “Actives” and reprograms their personalities to carry out missions for wealthy clients. In the pilot, which was revamped after Fox objected to Whedon’s initial offering, the Dollhouse concept is introduced and Dushku becomes a kidnapping negotiator. The result is a choppy episode that improves as the hour unfolds. Dushku, who was terrific as Faith on “Buffy The Vampire Slayer,” can carry the show but viewers will have to get used to her playing a different character every week. Fox did the right thing by scheduling the show on Friday night, paired with “Terminator: The Sarah Connor Chronicles.” Expectations are lower and “Dollhouse” will get the time to hit its stride.