(CNN) -- There's only one thing for sure about the future of the NBC network and that is that it will have to go on without current president and chief executive officer of NBC Universal, Jeff Zucker.
Everything else is up for speculation.
Zucker announced in an e-mail to employees on Friday that he will be leaving NBC Universal when Comcast assumes control of the company after the completion of a merger in a few months.
"It has not been an easy or simple decision," Zucker wrote. "I have spent my entire adult life here, more than 24 years. This is the only place I have ever worked. The only professional thing I have ever known."
Robert Thompson, founding director of the Bleier Center for Television and Popular Culture at Syracuse University, said the departure of Zucker was expected given the merger, adding that the situation was also not helped by "the Waterloo of Leno" referring to the ill-fated decision to give Jay Leno a prime-time show, which resulted in dismal ratings and Conan O'Brien losing his hosting gig at "The Tonight Show" to make way for Leno's return.
"[Zucker] did some great things at the network, but he will always be remembered for the Leno debacle," Thompson said. "The whole idea made a whole lot of sense, except for one thing: It wasn't a good program. The idea that Leno was going to be able to carry the 10 o'clock hour five nights a week was a gross miscalculation."
Zucker began his career in 1986 with NBC's Olympic unit before going on to various positions including executive producer of the "Today" show for nearly eight years. He became president and CEO of NBC Universal in 2007.
Zucker told the New York Times that he was well aware of his legacy regarding the Leno move, which he said was a risk "that simply didn't work out."
"Do I wish we'd had more success at NBC Entertainment in recent years? Yes, of course," Zucker said in an interview with the New York Times.
The long-serving executive also said during the interview that it was clear Comcast wanted to bring its own leadership, something he alluded to in his e-mail to employees.
"Comcast will be a great new steward, just as GE has been, and they deserve the chance to implement their own vision," Zucker wrote.
Thompson said Zucker's successor will have to develop the type of strategy that enabled the network to climb from a dismal last place in the ratings during the early 1980s to the home of successful programs like "The Cosby Show," "Friends" and "Seinfeld."
"What NBC network needs is really simple to say, but much, much more difficult to achieve," Thompson said. "That is it needs a couple of really, really big hits."
Marisa Guthrie, programming editor for Broadcasting & Cable, said NBC Universal's merger with Comcast comes at a time when the broadcast industry is changing.
"You increasingly will not be able to exist only as a broadcast network in the future," she said. "The programming costs keep going up as the ad revenue keeps going down, so there's got to be a tipping point."
Guthrie also points out that while cable programming gets the majority of the buzz with series like "Mad Men," broadcast television still has many more viewers than its pay-for-television counterpart. As popular as "Mad Men" is, she said, a show like Fox's "American Idol" still has many more people tuning in every week.
"Going forward, the Comcast guys are going to want to come in and put their stamp on the network," Guthrie said. "They are also going to want to find ways to achieve operational and programming synergies between their networks and NBC Universal."
The business models for cable and broadcast are totally different, she said, and there is a great deal of potential for Comcast to leverage NBC Universal's strengths with moneymakers like NBC Sports. Filling Zucker's shoes means having the ability to straddle the worlds of cable and broadcast, Guthrie said.
"Whoever comes in is going to have to really look at the balance sheet and there are going to be redundancies," she said. "They are going to have to look cross-channel and cross-platform synergies and there will be a lot of opportunities there."
Walter Podrazik, consulting curator of the Museum of Broadcast Communications in Chicago, Illinois, said NBC Universal has retrenched after the Leno incident, where they were trying to have more carefully budgeted prime time fare. Now the network has returned to traditional series like the J.J. Abrams helmed "Undercovers."
Podrazik said NBC Universal is an "accelerated microcosm" of the issues that broadcast networks face: how to appeal to viewers and keep them tuning in each week in an era when there is so much else vying for their attention and a multitude of choices.
He said each network has leaned on formulas and variations in recent years, be it CBS' "CSI" franchise, Fox's "American Idol" formula, NBC's "Law & Order" spin-offs or sitcoms like "The Office."
The merger between Comcast and NBC Universal is intriguing, Podrazik said, because of the many possibilities it presents for the industry as a whole in terms of a possible model.
"Does Comcast repurpose with some of its sports channels, does it go hand and hand with some of its affiliates, how does the presence of Telemundo factor in? Those are just a few of the questions," he said. "When you discuss where do you go from Zucker, it's more where do you go in the 2011 and beyond television universe."