"The Jay Leno Show" has struggled to attract viewers in its first few months, causing NBC to rethink its nighttime television experiment. To bring back the old Jay Leno magic, and his old ratings, the show is reintroducing some elements from Leno’s "Tonight Show" days. Is the old structure and look enough to save Leno’s new show? (Watch Jay Leno interview "Twilight"'s Taylor Lautner sans his desk)

The problem isn't the format, it's the time slot: Jay Leno's appeal and success were once tied into people falling asleep to his show, says Joel Keller at TV Squad, but at 10 p.m. viewers "don't have the same ingrained expectations" as when Leno aired at 11:30 p.m. Leno's trying to find an audience earlier in the night, but viewers "are looking for something interesting at 10."
"Leno show makes 'radical' format change; looks more like old Tonight Show"

Never bet on the conventional wisdom: NBC pushed Leno's best segments to the end of "The Jay Leno Show" because of an "insane belief that people would stay around for them," says Richard Rushfield at Gawker. Still, while you'd have to be "certifiable to bet on Leno and NBC at this dark hour," the “flood of bad press” might actually sweeten the odds a bit—“no one ever lost a buck betting against the wisdom of the press.”
"The beginning of the end of the Jay Leno experiment"

Leno’s not going anywhere anytime soon: NBC’s diagnosis of the “Leno Show” problem—“It’s too innovative!”—is unconvincing, says James Poniewozik in Time, but Leno’s job is safe. He’s “cheap” programming, and the odds of “very powerful people at NBC publicly second-guessing themselves” about Leno’s show are slim to none. If anything, Leno will move to 11, pushing Conan O’Brien to midnight—or NBC “could further screw over Conan” by giving Leno back “The Tonight Show.”
“Leno Show removing last vestiges of not-Tonight-Show-ness”