It is an odd job, even by Hirshberg’s standards. But that is apparently precisely why he was hired by Mark Willes, the former cereal executive who took over Times Mirror and its flagship paper in 1995. He’s making sweeping changes to meet his goals, which include doubling the Times’s daily circulation to 2 million. Hirshberg won’t reveal his plans, but so far he’s been prodding Times staffers with brow-knitting questions such as “What would be lost if papers ceased to exist?’’ His design staff is also spending time in malls, watching how people read newspapers. “It’s a much richer object to think about than I had ever imagined,’’ Hirshberg says. The redesigned paper should be parked on readers’ door-steps by next year.