“Merrimack River,” the opening song on Mandy Moore’s sixth album, Amanda Leigh, offers a sly look at her former life as a teen confection—back when her first hit, 1999’s “Candy,” was in daily rotation on Total Request Live, and long before she showed up on Entourage, posed for a Cosmo cover, and married Ryan Adams. “Candy-coated promise, just out of reach when you want it,” she sings, over an elegiac string arrangement of the sort employed by Alison Krauss. It’s pretty—and pretty boring. Every subsequent song on Amanda Leigh, no matter the tempo or mood, offers a similar mishmash of pop sheen and anodyne country rock, with little to suggest a distinct artistic vision. The best songs harness Moore’s booming, radio-ready voice, which is usually at odds with the album’s subtle arrangements. “Everblue” is a spare, tom-driven track held aloft by Moore’s assertive phrasing, while “Love To Love Me Back” jangles along with the sort of pedal-steel swoon and 12-string shine that calls to mind The Byrds (or, ahem, Gin Blossoms), but never sounds hokey or overworked. Both songs suggest that Moore’s interest in an expansive, high-lonesome sound could one day pay off. Still, that day isn’t here yet.