One might assert that the renewed appeal of this show should come as no surprise at all, given the major changes made by its many executive producers following the multitude of bad choices that crippled Idol during its last two seasons. That's certainly a valid observation: How could it not improve with a return to the three-judge format (after the clunky four-judge fiasco) and the elimination of celebrity guest judges who are not invested in the show during the crucial audition process?

Those big changes certainly helped, but it's the deluxe alterations that have really made the difference. I'm talking, of course, about the recruitment of legendary Aerosmith frontman Steven Tyler and multi-talented entertainer Jennifer Lopez to replace judges Simon Cowell and Kara DioGuardi.

Overall, I think Tyler and Lopez have been a little too soft in their support of many marginally talented amateurs -- one look at the formidable Mr. Cowell in that brilliantly scheduled Super Bowl ad for his upcoming Fox series The X-Factor instantly reinforced my suspicions that he would not have sat idly by and let a number of this season's hopefuls through to Hollywood -- but their participation this season swiftly set the "new" Idol apart from the "old" (as in "tired") one. The result has been a surprisingly sweet treat -- a wholly unexpected, twice-weekly surge of warm, feel-good television that has done much to take the unrelenting chill off what for most of the country has been a perfectly dismal winter.

When I first heard that Lopez was likely joining Idol -- before word came down that Tyler was also a contender -- I thought Jenny from the Block might bring a natural compassion to the show that had been lacking since the departure of Paula Abdul. I was willing to give her a chance, even though I had gone on the record with my concerns that adding even one huge celebrity to Idol's on-camera team would likely compromise a show that owed its phenomenal success to its unique ability to transform unknowns into stars. (I'm not talking about the contestants only. Simon Cowell, Randy Jackson and Ryan Seacrest were unknown to the American viewing public when Idol made its debut in 2002, and at that time Paula Abdul was a fading star at best.)

Lopez has indeed proven to be a fine addition to Idol this season, but the real surprise has been the fast-growing appeal of Steven Tyler. He's not just a bad-ass party boy. He's a warm, supportive, gently funny man with an ear for untapped talent -- a performer who can't resist performing when another talented singer hits the right notes. How charming was it to watch him not only express his admiration for so many of the would-be contestants but to sing along with them during their auditions? I thought putting unknowns at the mercy of larger-than-life superstars would, as they say in network offices, damage the DNA of the show, in such a way as to make it less pleasing to watch. But thanks to Tyler's unrestrained enthusiasm, just the opposite has happened (though I do long for those priceless moments when Cowell would unsparingly cut down the smug and the self-involved).

Given its troubling history with celebrity contributors -- up to and including the really bad decision last season to add judge Ellen DeGeneres -- I thought Idol in Season 10 should go with lesser known personalities: the stern but bighearted Gareth Malone of the BBC's tremendous observational reality series The Choir or Anastasia Brown, the life of the party on the much-missed Nashville Star. But I have to agree with a point Cowell made during a recent interview, when he remarked that it was wise of the Idol producers to make it into something new, which they certainly have, rather than to try to keep it as it was.

Still, I'm not going to fully retract my initial resistance to the addition of Tyler and Lopez until we're well into the live competition shows. That's when their new jobs will get difficult -- when they must repeatedly come up with smart things to say about the same contestants, being both constructive for the singers and engaging to the millions of people watching at home. Even before that, Tyler, Lopez and Jackson will have to prove they can cultivate a group of finalists in whom viewers will want to invest their time. As has been well documented, that ability seemed to utterly elude Cowell, Jackson, DioGuardi and DeGeneres last season. Similarly, two seasons back, Cowell, Jackson, DioGuardi and Abdul brought us only one memorable contestant -- the highly entertaining Adam Lambert, who has enjoyed far greater success post-Idol than that season's winner, Kris Allen.

Also in the weeks to come, we'll discover whether additional changes yet to be seen, including the contributions of music producer Jimmy Iovine as in-house mentor, are as pleasantly impactful and excitingly received as the talents of Tyler and Lopez. As this occasionally maddening powerhouse has demonstrated time and again, there are no certainties in the ongoing phenomenon that is American Idol.