When Ezra Pound said “Make it new,” he was not talking about teen soaps. So much of their appeal lies in their predictable storytelling and immediately recognizable characters: the beautiful girl group with the just-complicated-enough underbelly, the standoffish and misunderstood boys who’ll fall in love when the right girls come their way. Even Beverly Hills, 90210—which popularized, and arguably remains the apotheosis of, the genre—was bound by the formulaic demands of network television. When Brenda Walsh, played by Shannen Doherty, complains to her mom in the show’s first episode that she has nothing to wear and doesn’t “have the right hair,” what she means is that she’s a brunette in a world of blondes; complexity, variation, the unexpected and wholly new did not appear often on ’90s TV. Still, Doherty, who died of cancer earlier this month, was able to make something unforgettable out of Brenda. In a fictional world of tried-and-true tropes, she wasn’t a good girl or a bad girl; she was something more human altogether. Her smirk, those bangs, her roiling, earnest …