After 20 years and two blockbuster films, does “The Devil Wears Prada” director David Frankel really think “that’s all” for Miranda Priestly and her reign as the terrifying editor-in-chief of Runway magazine? “I said, ‘Never again,’ and here we are,” Frankel says with a laugh. “So, I certainly would never say, ‘Never again,’ again.” Not that Frankel wasn’t on board for a sequel to the haute-couture comedy in theory — the 2006 film made $326 million at the box office, after all — but all the stars had to align for another movie to make sense, beginning with the return of Meryl Streep as Miranda. “Annie Hathaway has a great analogy for the experience of making the movie,” Frankel says, quoting his leading lady who returns alongside Streep, Emily Blunt and Stanley Tucci. “We were getting the band back together for a new album and going on tour and playing the new songs, but the audience also wants to hear the old hits.…