I would put more models in general on the cover: Arlenis Sosa, Hilary Rhoda, Lily Donaldson, Jourdan Dunn, Kristen McMenamy, and some fresh faces who are just breaking onto the scene.
I would have more high/low fashion spreads. Pairing something from Target with something by Chanel (Lagerfeld would probably kill me, but anyway).
I wouldn't put Gwyneth Paltrow on the cover for at least a full year. Or maybe more. Or maybe forever.
I would accept short story submissions from writers whether they were previously published or not. Vogue used to do this back in the day. I think it's a great way to discover new talent. Plus, short fiction rocks.
I'd have less society pages. They'd still be there, just not as often. I know the socialites featured probably donate money to Vogue or whatnot. But they'd have to settle for being featured less often. Unless someone truly fabulous came along. Someone like Babe Paley.
My motto would be: Always keep them guessing. I'd keep readers on their toes, wondering what would be in the magazine for next month. In other words, I'd try not to be as predictable as the current Vogue.