The Times news broadcast has emerged as the most promising show on WAMI, Barry Diller's year-old effort to create the most glamorous UHF station in the world. Mankiewicz, host of the 10:00 p.m. Times, is already the sharpest anchor on the local airwaves. Admittedly it's a matter of style. Mankiewicz appeals to viewers who don't want their news anchors to be benevolent parents. He never invites his audience to join the WAMI family, for instance. Nor does he spout the banal chitchat that emanates from most anchor chairs. His delivery is self-deprecating. It's also professional and engaging. Serious tinkering is still needed before the The Times becomes the essential viewing it has the potential to be. Until it reaches that goal, Mankiewicz makes the show more than bearable.