There are lots of reasons plot threads go unresolved on continuing TV series. Sometimes the show ends prematurely. Sometimes the network interferes. Sometimes the ongoing story of the show evolves in a way that doesn't allow the writers to revisit it. And sometimes the writers just want to move on. "Sliders" ran the gamut of all of those. It wasn't the first show to have to do so, and it definitely wasn't the last (I'm looking at you, "Lost"... seriously, what the fuck was 90% of your show about?). But some of these little unresolved plot threads always bugged me, and that hasn't changed upon re-watching the show.
When I talk about "unresolved threads", I'm talking about clearly written plot developments that were left hanging and for some reason or another never got picked up again. I'm not talking about plot inconsistencies, like Maggie's sudden loss of military acumen between Seasons 3 and 4, or the Professor's encyclopedic knowledge of literally everything from physics to Shakespeare.
As for the ones I've chosen, I'm not sure exactly what to call these. They're not quite the "best", and "favorite" doesn't seem right. I guess these are, in my opinion, the five most "intriguing" from the five-season run of "Sliders."
5. The Final Cliffhanger
It's not really accurate to say "Sliders" got canceled "too soon", since it did run for five seasons, but when your show ends on an unresolved cliffhanger, that's kind of a bummer for your longtime fans. In the final episode, Remmy slides solo through an unstable vortex, headed for Earth Prime* with a weapon that will wipe out the Kromaggs. But a seer has told the gang that they'll die on their next slide, which is why Remmy slid alone. We still don't know if he made it, but I'd like to imagine that he did.
*Aside, I'm not sure why, by the team we reached the end of Season 5, Earth Prime was still such a big deal. Well, I know why from a creative standpoint -- it's supposed to be OUR Earth -- but what's the group's motivation. Remmy is the only character in the group who's from Earth Prime.
4. Ryan, the Lottery Winner
At the end of Season 1, the group slid off "lottery" world with a new member, Ryan (the lottery winner that Wade had fallen for, and wanted to save from death). Also, just as he was leaping into the vortex, Quinn was shot, and seemed to be near death when emerging. However, when Season 2 rolled around, there was a brief dream sequence (in which Quinn dreamed his own funeral, with Ryan in attendance) and then Ryan was never seen again. They made reference to him helping save Quinn's life, and him asking Wade to stay on "this world" (whatever that world actually was), but he was never seen again. What happened to him on that world? Who knows? We have FOX and their creative interference thank for this mess.
3. Colin and Quinn's Real Home World
In Season 4, after the show had shifted from FOX to Sci-Fi, we get thrown for a major loop when we learn that Earth Prime isn't really Quinn's homeworld: his real parents were sliders, and they took him and his brother to separate worlds to keep them safe during the Kromagg war*. They returned for them later, but Quinn's new parents kept him hidden, while Colin's had died, and he bounced around. In "Slidecage", we discovered that "Mallory Prime" (as I'm calling it) had won the war against the Kromaggs, but built the slidecage to keep their world safe. It looked like Quinn and Colin finally got home in the Season 4 finale "Revelations", but that turned out to be a twist of its own. So what really happened with "Mallory Prime" (usually called "Kromagg Prime" in the Sliders universe)? We have no idea.
*Interestingly, there was a whole different plan for Colin's origin in Season 4. The popular "Sliders" fan site "Earth Prime" has the inside scoop on what I think would have made for a much cooler Season 4.
2. The fate of Logan St. Clair
Even before rewatching the episodes, I would have pinpointed this as one of the unresolved plot threads that pissed me off. In the Season 3 episode "Double Cross", we meet a female double of Quinn's, who also has access to sliding technology. At the end of the episode, she tracks the Sliders to their next world. After a standoff, she gets sucked back into her vortex, and we learn that Quinn set her timer for random sliding. Rembrandt asks, "she said something about tracking wormholes. Are we going to run into her again?" There's no response from Quinn, but the obvious implication is "yes". But we never do. Allegedly, FOX execs thought Zoe McLellan, the actress who played Logan, wasn't "hot" enough to be a recurring villain. That sucks.
1. "Post-Traumatic Slide Syndrom"
A.K.A. "Which Arturo did they take?". Now, in-depth "Sliders" fans know that show creator Tracy Tormé has said that the intention as written was that the group slid with the Arturo from "Azure Gate Bridge World" and their Arturo was left behind, but for various reasons they never got back around to that plot, so they dropped the alt-Arturo idea entirely. Personally, I think that sucks, and it kills me that they weren't able to resolve this mystery IN-universe. Obviously the "more action" direction from FOX, along with the falling out with John Rhys-Davies, prevented that. If in fact the group slid with the original Arturo left behind, then it means that at the time of the series finale, it's entirely possible that he's still alive -- and didn't have to suffer the indignity of the embarrassing death the writers thrust upon Arturo in "The Exodus". Personally, I would have loved it if they could have revisited that world in Season 4, with Quinn having to fill the real Arturo in on Colin, the Kromaggs and even the death of the alt-Arturo. Their reunion would have made for some incredible drama, and getting Rhys-Davies back on the show would have been a masterstroke for Sci-Fi. Instead, we'll always be left to wonder "what if?"