Thus far, we've focused almost exclusively on highly recognizable network (+HBO and now streaming) shows that were a big deal at the time. Also*, we're generally going with shows people think started off as very good shows. What if we open the discussion up to, say, non-HBO cable tv shows and first run syndication** shows and such; as well as shows that only ever started at 'okay?' I'm thinking things like
Stargate SG-1 or
The Magicians or
Time Trax. Not them specifically, since I can't remember what their 1st seasons were like compared to later ones, but those kind of shows.
*possibly with the exceptions of WoT, RoP, and HotD; YMMV
**other than ST:TNG
First vote would be
Andromeda. The idea was not bad -- Roddenberry had been fleshing out the Dylan Hunt/fallen 'federation' storyline over the course of a number of series pitches, actually bringing that to fruition was not a ridiculous notion. Nor was casting Kevin Sorbo, who at the time was just 'the guy from
Hercules' (another smarmy hero in charge who would be overconfident if not for being just-that-good). And the first season was... fine. Nothing to write home about, and mostly episodic stuff that resolved the plot of the week and got us used to the characters. However, not far and away obviously worse than the first seasons of similar shows that went on to end up being great (like
Deep Space Nine or
Babylon 5), and honestly better than season 1 ST:TNG. It was only after Robert Wolfe left that it became obvious that they didn't know where to take it and that Sorbo had no range.
Another one is
Beastmaster. This one started out aiming even lower -- it was trying to replicate the model/ride the wave of
Hercules/Xena with camp and action and exposed flesh. And it was perfectly fine at that model. My wife tells me that Daniel Goddard is very easy on the eyes, and I find the season one baddy (King Zad) a wonderful scenery-chewing performance. Then, like fellow syndicated show
Earth: Final Conflict*, it ran into casting issues. People couldn't fit the next season into their schedule or whatever, and so the cast (and story) had to be re-written with every season.
*which doesn't match the thread premise, as I think seasons 1-3 are all of similar quality
There was a third example I had that isn't coming to me right now. If I think of it, I will post it as well.
Firefly.
I love it but....
I'd agree with Firefly, but for a completely different reason: I want to see the rest of season one that was never filmed! I'd really like to have multiple seasons, but at this point I'd be happy if they had been allowed to make one full season.
I want the rest of season one I have in my head to be real. What we've heard about the plans for the second half of season one are not particularly great. Regardless, I am with darjr on no more than one season. The premise of being one step ahead of the law, one behind the next paycheck does not lend itself to a long series.
I also watched all of Supernatural in it's first run. I will stand up for the later season being highly worth while. There are highs and lows, some seasons are absolutely better than others, and even the so-called best seasons have some major rough spots. But overall it's great.
One of the big things about Supernatural is that it only works if you enjoy the filler.
This reminds me of how a friend who still watches talks about
The Simpsons. By the time the show had ironed out the rough spots, it also was past what people think of as the golden days; and* there's no clear point where it truly 'got bad,' so much as vacillated in quality and in how much of it was filler ever since.
*supposedly, I stopped watching some time in the early 90s.
So an interesting segway on this thread are shows with horrible endings. Not meh endings, not "eh not my favorite", but "this show is now ash in my mouth" kind of endings.
Its an interesting question of if you had a great 1st season and the next several seasons were solid, but then the ending was god aweful, would it have been worth cutting out all of those other seasons just to have a 1 and done without the bad ending?
I am a strong proponent of the notion that a strong final episode is
not the most important thing for a show to have (better than a bad one of course, just not very important). A great capstone does not make everything leading up to it retroactively better, and a single bad episode at the end does not retroactively spoil what came before either.
Game of Thrones and bad last two seasons or something like that is a different matter, although even then I think it is only because people were so invested in where things were going that it has made the previous 6 seasons unwatchable to so many.
None quite that bad spring to mind (they may later), but what about shows that managed a perfectly good ending, but then got renewed and pretty much wasted them. I remember Elementary wrapping up really well in season 6, but then getting a seventh season.
Uncancelled shows are another beast as well. They are even better for this, since you can just pretend they didn't happen and still get your closure.