When the character of Janeway was being developed, the producers weren't sure if they were really going ahead with the first female Trek lead, and spoke to British actor Nigel Havers about the role, as well as Alien Nation actor Gary Graham (who also claims to have read for the role of Sisko). Graham would later guest star as Kes' evil foil (in "Cold Fire"), and on Enterprise as Soval, a skeptic-turned-ally of the Federation.
In addition to the initially-cast Genevieve Bujold (see immediately below), many other well-known actresses were considered for the role of Captain Janeway, including Lynda Carter, Patty Duke and Linda Hamilton. Note that, unlike Bujold, all of these actresses were TV veterans and would have been accustomed to the aggressive shooting schedule on Voyager from the get-go.
Janeway was the first regular Trek role to actually be recast before the series aired. Initially Oscar-nominated actress Genevieve Bujold was cast as Captain Nicole Janeway. After she departed, the character's name became Elizabeth Janeway and only became Kathryn when Kate Mulgrew was finally cast and the name seemed to suit her better.
For that matter, even before the Locarno/Paris idea (see below), the producers wanted this character to be Ro Laren, which would have made sense as she was now Maquis. The plot of TNG's "Preemptive Strike" was meant to allow a way for her to join the crew of Voyager. However, just as with DS9, Michelle Forbes didn't want to commit to a series. The writers started thinking about what other "fallen" characters could be used, and came up with Locarno, who eventually became Paris.
Brannon Braga toyed with the idea of having Sarah Silverman join the show full-time on the strength of her guest role in "Future's End", and perhaps have her character enter into a romantic arc with Tom Paris.
Early in planning, Worf had been suggested as being part of the crew. The idea was dropped when Michael Dorn chose not to pursue the role.
Janeway was initially going to be a lesbian before the producers chickened out. Kate Mulgrew herself was very supportive of the idea, and this is still a major stick in the craw of many fans, given that the franchise would not feature an explicitly homosexual characternote Jadzia Dax appears to be bi, though the fluidity of joined Trill gender identity makes this a weird case. until Star Trek: Discovery in the late 2010s.
Tom Paris was originally meant to be one-off TNG character Nicholas Locarno, an expelled Starfleet cadet also played by Robert Duncan McNeill in the TNG episode "The First Duty". Under WGA rules, the writers of the episode, Ronald D. Moore and Naren Shankar, would get royalties for every episode Locarno appeared in. Reasons for changing it included the royalties and the more plausible idea that, unlike Tom, Nicholas was "irredeemable". And so the writers instead created Tom Paris, with a very similar backstory but with a few differences: an Admiral for a father, kicked out of Starfleet for lying about an accident, and joined the Maquis before being captured and imprisoned. McNeill believes they are vastly different characters, as Paris, for all his Bad Boy tendencies, was good at heart, which he doesn't believe is true of Locarno* case in point, Paris eventually came forward about his lie even though he could have gotten away with it, while Locarno only confessed after Wesley had already revealed the truth. However, it's impossible to say how Locarno's character might have evolved if the original plan had gone forward.
Incidentally, Tom Paris follows the same naming convention as Nicholas Locarno. Both have a common first name and a European city for a last name.
The Caretaker and his mate, Susperia, were written with the ability to return Janeway's crew to Earth instantly if ratings plunged.
"Non Sequitur" was originally supposed to feature Counselor Troi as the one grilling Harry Kim in the alternate timeline instead of yet another random Admiral. The creators were unable to get Marina Sirtis on short notice. (She did appear with Reg Barclay a few seasons later.)
Michael Piller favored an increasing sense of desperation. Additionally, he pushed for a growing cast of less-than-sterling crewmen like Seska, Jonas, and Suder. Jeri Taylor disliked each of these characters and killed them all off in time for Season Three. Brannon Braga also categorically stated that he doesnt like threading other writers' arcs or characters into his own episodes, so the serialized approach was thrown out.
This greatly changed the outcome of the Season Two closer "Basics". Piller's script originally had Maj Cullah and Seska's baby dying, and Seska escaping with Lon Suder in tow; As it turns out, the exact opposite happens. The showrunners wanted to close the book on the Kazon due to plummeting ratings.
In the episode "Favorite Son", it was considered making the reveal of Harry Kim as a Delta Quadrant alien a real, permanent change to the character. While the in-universe explanation probably would have been a Voodoo Shark, nevertheless, there would have been a fine poetic irony in Harry — the character most eager to get home to the Alpha Quadrant — actually turning out to be biologically native to the Delta Quadrant.
At the end of season three, either Harry Kim or Kes was slated to be killed off to make room for new character Seven Of Nine. Neither were killed off in the season finale, but the more likely candidate, Harry Kim, was seriously injured so that he could die in the fourth season premiere. Between seasons, Garret Wang ended up listed on People's list of 50 Most Beautiful People, and the Executives mandated that he had to stay — so they wrote out Kes instead. This is especially ironic given Rick Berman's mandate that the alien characters be more interesting than the human ones.
Jeri Ryan has said that she read two different scenes when she auditioned for Seven of Nine. One was the rather notorious Do You Want to Copulate? scene, which ended up being filmed (and she admits to hating it to this very day.) The other was apparently a really beautiful, touching scene where Seven first experiences laughter, and she seems to honestly regret that scene never made it to film.
Braga did say that if Voyager was up to him, the show would have frequently been like the fan favorite episode "Year of Hell": enemies on all sides, dwindling resources, and crewmen pushed to the ends of their rope. Additionally, the Year of Hell was not originally just a two-parter but instead the plan for the entire fourth season—until the executives put a stop to that, reducing a grim and gritty season to a Dallas cop-out.
It was, indeed, foreshadowed in the season three episode "Before and After", where Kes' time-jumps were caused by a Krenim temporal weapon lodged in Voyager's hull. Kes would leave shortly into the fourth season, however, which prevented her from participating in "Year of Hell", thus nullifying the events of "Before and After". In said episode, it showed a future in which where Janeway and Torres were killed off, leaving Chakotay in command of the ship. It also had Neelix as a security officer, and probably would have had some interesting plots later on.
Indeed, a version of the first part of the Year of Hell was originally going to be the third season finale, but it was changed to "Scorpion" to capitalize on the recent release of Star Trek: First Contact and the use of the Borg.
When the Borg tactical cube was in the planning stages, Doug Drexler sketched up a "pyramid" version, to reference the first UPN logo, which consisted of a circle (the Borg sphere), a triangle (the "Paramountain"), and a square (the Borg cube). It was only a joke sketch, though.
After he left Voyager's writing room, Ron Moore went on to create his own version of a show about a bunch of people stranded in hostile space, without access to any sort of friendly infrastructure, trying to survive and make their way home. It was called Battlestar Galactica (2003) and it received significantly better press coverage and critical reception. One wonders what VOY would have looked like had he stayed.
The original intention behind the show was to have the ship start off pristine and a full Starfleet crew, then acquire a number of Maquis rebels, criminals and vagrant locals as they continue their journey home. Over time the ship would get banged up and, without a starbase to make repairs or Federation relief, would gradually descend into a more dramatic survival story as every bit of damage carries over to the next few episodes. The show was heading towards that kind of serialized storytelling in the first two seasons, but the underwhelming response to the Kazon and their own early Story Arcs lead to wiping the slate mostly clean for the third season, and from there settled into Status Quo Is God. We still saw bits and pieces of this original idea, a natural part of the premise, but the ship never seemed to be in too bad of shape and the crew mostly just got along. This is one reason why the "Year of Hell" two-parter was so beloved by both cast and crew, as it took it to the logical conclusion (we see pieces of the hull coming off when they go into warp, and at one point an entire deck implodes). note Rather notably, this premise was translated to the third season of Enterprise. While it had its own detractors, most everyone agreed it gave the show a much needed shot of adrenaline.
"Common Knowledge" aside, there was nothing stopping the writers from returning the ship to the Alpha Quadrant. In fact there was a desire on the part of the producers to do this from very early on; the show would have continued with the Voyager in the Alpha Quadrant as just another Starfleet ship. Apparently the only reason they never did it (even though practically everyone on the writing staff was onboard with the idea) was fear of the fallout from such a massive Retool.
Speaking of the Year of Hell, the original intention was for it to last an entire season, actually showing the ship getting steadily more beaten up, the crew more wounded and tired, and dealing with the ramifications of the events shown in the two-parter over the course of many episodes. The idea was eventually discarded, for a lot of reasons: continually messing with the ship model (they were still doing physical effects at the time) and keeping continuity on its damage would have been a pain, the risk of Darkness-Induced Audience Apathy was considered much too high, and certainly had they used the Reset Button ending in the actual plot and wiped out an entire season it would have caused an extremely furious response in a fanbase that was currently very loudly antagonistic on the internet.