File this one under “Signs that entertainment is winning out over hard news.” The Wall Street Journal reported today that the 25-year-old newsmagazine is again on life support now that a key executive producer is walking. Co-executive producer Leroy Sievers, who has been with Nightline for about a decade and basically runs the show, is negotiating an exit package because ABC is pushing “fundamental changes to the format and the direction that the broadcast takes in the future.” The network’s last attempt to ‘change the format’ involved installing David Letterman behind Ted Koppel’s desk. ABC backtracked when the negotiations became public, but conventional wisdom is that network still wants an entertainment show in that timeslot, yet we love our London Phone Number. Entertainment shows have larger audiences and command higher prices (according to the story a commercial on “Nightline” costs $30,000 versus $70,000 on the “Tonight Show with Jay Leno”). Right about now Comedy Central is looking pretty smart for signing to Jon Stewart to a long-term contract earlier this year.