There's obviously been much fan speculation over the last thirty years about what the second season of Battlestar Galactica might have been like, had the show been properly renewed, rather than canceled and then half-assedly resurrected a year later as a cut-rate kid's show. Entire comic book series have explored possible storylines, there have been original novels and tons of fan fiction.
But I've seen very little actual realistic speculation about what a 1979-1980 television season might have been like. Most of the stuff I've read has postulated exciting storylines that would have been very cool for the fans, but incredibly expensive to actually have produced. So, based on my understanding of 70s network television and trends witnessed in Season 1, here's what I think we might have seen, had ABC decided to give the series a last-minute renewal:
The first season was made up of basically three types of story. The first third of the season consisted of several "Apollo/Starbuck crash on a planet" episodes, with plots that were basically TV Westerns ("The Long Patrol," "The Young Warriors"). Then, there were the big, two-hour "epics" like "Gun On Ice Planet Zero," "The Living Legend," and "War Of the Gods." And, finally, there were the "bottle" shows, set entirely on the Galactica or within the Colonial fleet, centered more on characters rather than action ("Murder on the Rising Star," "The Man With Nine Lives," "Take the Celestra!").
Had the show gone to a second season, I think we would definitely seen a lot more of these "bottle shows." ABC and Universal were both uncomfortable with the high cost of the series (specifically the effects), and it was the show's budget more than ratings that got it canceled in the first place. And we saw with Galactica 1980 that ABC still had interest in the concept if it could be produced cheaply (too cheaply, in 1980's case). There would have almost certainly been a lot of behind-the-scenes belt-tightening, and it's a safe bet that we would have seen a lot more stories set within the Colonial fleet.
Now, I probably wouldn't have minded that too much, since I was fascinated by Colonial society, and some of those later episodes are among my favorites. Seeing the writers explore the fleet culture - not to mention the core characters - probably would have been a good thing. We might have gotten some detail on daily fleet life for civilians, more info on the various classes (Sires? Siresses?), and a look at the economics of the survivors' situation. There would almost certainly have to be some sort of Black Market and criminal element. And, I would personally like to have seen more of the Borellian Nomen... and discover what other interesting subcultures might have existed among the Colonials.
Unfortunately, I think we would have seen a reduction in the cast, too. Battlestar Galactica had a huge regular cast, and once it got going, many characters featured in the opening titles ended up being marginalized or forgotten. My beloved Maren Jensen - beautiful as she was - probably would have been written out. At the end of the first season, she'd already disappeared - she hadn't been seen since "Greetings From Earth," where she'd been depressingly reduced to the role of "school marm." Although originally intended to be both one of the prominent Viper pilots and a love interest for Starbuck, it hadn't worked out that way, and she'd spent most of her time riding a computer console on a corner of the bridge, chewing her lovely lip.
Tony Swartz' Flight Sargent Jolly would probably have completely disappeared, along with some of the other semi-regulars. I also suspect that Herb Jefferson as Boomer might have found himself cut loose, since his role as Blue Squadron's third musketeer had been mostly supplanted by Anne Lockhart's Sheba. I also don't see much of a continued role for John Colico's delightful Baltar; as a convict on the prison barge, there's not much he could do to menace the fleet, and even if he escaped (again), would the Cylons realistically want him back?
Speaking of those chrome-plated pursuers, we probably would have seen considerably less of the Cylons, as well, with the producers saving them for sweeps week "events" to pump up Nielsen numbers. ("The Cylons are back!") This would be when we'd get the slightly more extravagant two-hour/part "epics," although there would definitely be fewer of them. One such "event" would almost certainly have involved the return of the Battlestar Pegasus and its legendary Commander Cain (if Lloyd Bridges' fee could be budgeted), since such a story would be able to use a lot of stock combat effects shots and standing sets. (Would Cain have approved of Sheba's involvement with Apollo? Would he have wanted her to rejoin him on the Pegasus? Hmmm...)
Considering Glen Larson's interest in the spiritual, we likely would have also seen a lot more of the Ship of Lights and its enigmatic, angelic crew and a return appearance from Patrick MacNee's Count Iblis. What we probably wouldn't have seen, although most of the show's young fans would have loved it, were any more non-human aliens. Oh, we got a few early on - the Ovions and the "Android Sisters" in the pilot, the pig-like Borays in "The Magnificent Warriors" - but elaborate make-ups and/or masks would certainly have been prohibitively expensive. Most likely, we would have met more human cultures/colonies along the lines of the Terrans from "Experiment in Terra," and Adama would speculate that this meant they were following the path of the Thirteenth Tribe in the right direction.
More character-driven stories would have led to more soap opera stuff, with additional screen time devoted to Apollo and Sheba's budding romance (and Starbuck and Cassiopiea's as well). One episode we know would have appeared for sure, is the one that formed the basis for 1980's "The Return of Starbuck," although the ending would probably been quite different. The Battlestar Wiki also lists a few other unproduced scripts that might have been reworked into year 2 episodes; from the synopses on the site, "Two for Twilley" and "I Have Seen Earth" could have both been produced under the budget-conscious conditions I postulate in this essay, and "Showdown" and "The Mutiny" might have made decent double-length event episodes.
Buck Rogers (just as Buck co-opted several Galactica props and models for its purposes). Teenage fans like myself probably wouldn't have minded too much, as long as there were still spaceships zooming across the screen, but it wouldn't have helped the series' reputation or longevity.
If the show had been renewed and had resembled what I've speculated above, I doubt it would have gone on to a third season. The history of science fiction on American network television, up until Star Trek: The Next Generation (and that was syndicated, and thus spared the interference of network execs), is of two-or-three season runs, with diminishing production values and story quality. In fact, until the aforementioned ST: TNG, the longest running SF adventure series on U.S. television was Irwin Allen's Voyage To The Bottom of The Sea in the 60s, and that show perfectly illustrates the standard trajectory of genre shows prior to the mid-80s. Each season the budgets got smaller, the production values diminished, and the scripts got sillier as the writing staffs ran out of ideas and resources. Effects shots were endlessly recycled and the stories became more and more set-bound.
Still, when all is said and done, I would still have rather seen a second season along the lines of what I imagined here than Galactica 1980....