Inside CBS and Viacom, there are many execs who believe the companies shouldn’t have split in 2005. But after 15 years of operating independent of each other, some of those same execs weren’t so sure the two sides should get back together.

But the media landscape has dramatically changed in the years since Sumner Redstone pulled his two companies apart, and inside both CBS and Viacom, there has been a sense for some time that the reunion was inevitable — and this time, might be more functional.

Said one insider: “There’s a sense of relief, as this has been in the works for a long time… excitement, with some anxiety.”

Plenty of questions remain, including the usual uncertainty of what kind of job loss might come with consolidation. Staffers want to know what it all means — and there are no quick answers. Viacom and CBS already operate lean programming teams, but there will likely be some trims in back offices such as human resources and IT. However, unlike the recent Disney/Fox merger (where plenty of divisions overlapped), Viacom and CBS mostly operate unique businesses — keeping concerns about massive trims, at least at this moment, to a minimum.

“Those were public executions,” one source said of the Disney/Fox realignment. “There will be some redundancies here, but there’s not the same substantial overlap.”

Beyond the usual apprehensions about whether further changes are coming, at the moment, the big question internally is how much synergy will be encouraged and expected between the two organizations, and how soon. For execs who were around during the previous merger, they remember the mandate was a bit tepid: Cooperate, but don’t expend any serious resources to do so. “There was no reward for being a good guy,” one exec said.

That may be different this time around, and insiders are particularly interested to see what this means on the digital side. The idea of building up CBS All Access with content from Viacom networks such as Nickelodeon and MTV, and incorporating CBS outlets into Pluto TV, seem like logical ideas on paper — how likely will that actually be?

As many internal CBS/Viacom sources pointed out to Variety, it’s only been a day since the merger became official and they could finally discuss Hollywood’s worst-kept secret. But that doesn’t mean the answers are free flowing just yet.

For now, there’s a feeling of a bit of status quo, particularly given the fact that the companies’ key leaders are still in place. At CBS, Joe Ianniello has been lauded for calmly steering the ship and offering a steady hand after the tumultuous exit of former CEO Leslie Moonves. And under him, David Nevins continues as the creative leader for CBS, Showtime and Pop even as Showtime and Pop move to the Viacom side.

“It’s nice to see the leadership of the company has stayed intact,” one CBS source said. “They didn’t blow up the company.”

With Ianniello losing oversight of Showtime, however, there is some question of how long this structure might last, or if his role as chairman-CEO of CBS under Bakish is a transitional position. Showtime represented a chunk of revenue in Ianniello’s portfolio that he’s no longer in charge of. Making him the COO and No. 2 of the whole company, under CEO Bob Bakish, might have made for a cleaner set up, but it’s believed Ianniello craved some degree of autonomy.

Over at Viacom, there’s also relief that Bakish, widely lauded for helping course correct a company that had been floating astray, remains in charge. “The Bob of it all is so great,” said one exec there, who also lauded Christa D’Alimonte, named executive vice president, general counsel and secretary of the merged entity. “Christa is also a superstar. With Bob running it and Christa as general counsel of the combined company, it can’t get any better than that.”

On the Paramount Pictures lot in Hollywood, staffers are feeling invigorated by the news, multiple people familiar with the operation said. Executives in creative and business affairs feel the OTT platform CBS All Access has, overnight, put Paramount in the streaming game. While some are curious about what overlap CBS will present in the coming days, the studio has full confidence in the leadership of TV chief Nicole Clemens, who has ramped up the production slate and has proven to be effective in less than a year on the job.

The film group was relieved to see studio chairman and CEO Jim Gianopulos sign a new, multi-year deal to continue his turnaround efforts, announced just before the merger bid came through. Elizabeth Raposo, head of production and known internally as a shepherd of big film franchises like “Mission: Impossible” and “Transformers,” was also extended.

Ianniello’s and Bakish’s Tuesday emails to staffers were well-received, and Bakish also addressed all of Viacom on Wednesday in a global town hall, streamed from New York headquarters to places like the Paramount Theater on the studio’s Hollywood lot. He spoke for about thirty minutes, and took questions for another thirty.

“As first impressions go, this went well,” an insider said of the outreach inside both sides of the company.

Now, with regulatory approval pretty much a foregone conclusion, the overall mood is pretty much, “what’s next” and and anxiousness to play catchup to the rest of the industry. “I think there’s some excitement at the possibilities we can do as a combined company,” said one exec. “It’s go time.”

[Matt Donnelly contributed to this report.]