To savor New York Times columnist Maureen Dowd at her incisive, stiletto-wielding best, check out her already legendary Oct. 22 hit piece on colleague Judith Miller. To observe Dowd at her coquettish, stiletto-wearing worst, crack her new book, Are Men Necessary?, a hodgepodge of recycled columns, Dorothy Parker quips, and peekaboo glimpses into the glam journalist's personal life. Her subject is the sexual revolution's screwy legacy, from Anita Hill to Botox, and she serves up some dishy tidbits like her run-in with Monica Lewinsky (''a volatile blend of brassy and deeply vulnerable'') in a Washington restaurant. What's missing is a strong point of view to pull it all together. Dowd describes herself as a ''fun-loving...Carrie Bradshaw type,'' and the analogy extends to these fluffy musings.