UPDATE 2-"American Idol" ends on low, questions over future

* "American Idol" finale lowest TV ratings since 2004

* Season 8 ends with future of 3 judges in doubt (Adds Randy Jackson, Ryan Seacrest contracts, line 34)

By Jill Serjeant

LOS ANGELES, May 21 (Reuters) - Kris Allen's upset victory over glam rocker Adam Lambert drew the smallest "American Idol" finale audience since 2004, slowing the television ratings juggernaut and raising questions about the future of some of its key players.

Preliminary figures from News Corp's Fox network on Thursday showed an estimated 28.8 million people watched the two-hour finale of the popular TV singing contest on Wednesday, down from 32 million last year.

While still America's most watched TV show, "American Idol" audiences have slipped to an average 26.3 million per twice weekly episode over the five-month broadcast, compared to a 2006 high of about 30.8 million.

The slide came despite producers adding a fourth judge, Kara DioGuardi, to keep the show fresh. DioGuardi, a songwriter who helped pen the poorly received first single "No Boundaries" for Kris Allen, now must wait to hear whether her one-year contract will be renewed.

Erratic panelist Paula Abdul's contract expires with the end of the current season and often-acerbic British judge Simon Cowell -- arguably the show's biggest asset -- has discussed leaving when his contract is up in May 2010.

Cowell commutes weekly across the Atlantic to run his British-based shows "The X Factor" and "Britain's Got Talent" and has said he would want to leave if "Idol" was toppled from its six-year reign at the top on U.S. television.

An AOL Television poll this week found that 49 percent of "Idol" fans questioned would no longer watch if Cowell leaves.

Record producer and judge Randy Jackson's contract also expires in 2010 along with host Ryan Seacrest but the pair have not publicly indicated their wishes.

'LOST THE CHEMISTRY'

Contract talks are expected before nationwide summer auditions begin for the next season of "American Idol," which will be broadcast in early 2010. Negotiations will be primarily in the hands of joint producers 19 Entertainment and FremantleMedia.

Fox executives have said they hope all the judges will stay.

However DioGuardi looks to be most at risk, despite a bikini-strip singing stunt on Wednesday regarded as a finale highlight.

Nigel Lythgoe, a former executive producer with "Idol," said he would never have agreed to four judges.