Babylon 5 and British serials, like Blake's 7 and Doctor Who were there earlier; but, Babylon 5 had a definite ending in mind (Game of Thrones sort of does, though it has been a bit fluid, after they passed the printed material).

Serial storytelling usually falls into a formula. The pulps had them, genre novel series had them, tv has them, and film franchises have them. It's kind of necessary to churn out endless product. The problem that is, after a while, you notice the formula more than the stories and it usually means it is time to move on.

I read about 3 Doc Savage novels, after hunting down any I could fine, only to find that the formula was pretty obvious, fairly quickly, and left a stack of them unread, before getting rid of them. The original Fleming Bonds were very formulaic, with the mission laid out, flemings long descriptive passages of the locale, Bond's clothing, his meal, investigations, counter moves by the villain, rescue of the damsel and climax, with the wind down for an epilogue. It carried over to the films, with the formula really only changing when the role did, depending on the strengths of the actor. With Moore, they added more sight gags and double entendres, with the big stunt set piece somewhere in the middle (though with a few in the teaser). The violence was cartoonier than Connery's time, though his films were starting to go there (Diamonds went fully there). Dalton pulled back into more serious territory, though the big stunt pieces remained. Brosnan mixed a bit of both, with big stunts in the teaser and the middle. Craig moved into deadly serious, with the crashing buildings in the climax and brutal chases in the early stages.

Good Lord! Are we going to agree twice in a millennium?

I think they suffer from having one drawn out plot with one Big Bad. Even if they didn’t take down the main villain until the end of the season it would still help to have another story-arc within the season.

To be clear, I don't necessarily think that formulaic is always bad. It just depends on the execution. The CW shows are starting to look like they are using a template with interchangeable pieces. Agents of S.H.I.E.L.D. has been a bit more interesting, because for the last couple of seasons they have gone with the approach of breaking up the season long story into shorter arcs, which I think has been working well.

Again, I'm not saying superhero shows need to abandon their roots -- by their nature, they need to abide by certain tropes, and I don't have a problem with that. But I'd like see the writers take the tropes in new ways, maybe taking cues from other TV shows. For example, shows like Smallville and Lost both had their season-long arcs, but they also had overarching mythologies that carried over from season to season.  Star Trek DS9 told a serialized story, but it didn't necessarily fit into the confines of a "villain-of-the-season", and did a pretty good job of balancing between done-in-one episodes that are typical of Star Trek and episodes which were part of the larger story.  And from what I recall, the Dominion War actually played out over the course of something like 3-4 seasons, if you count the foreshadowing, build-up, and the actual war itself.  I'd like to see a superhero show do something with a villain who is the hero's adversary over the course of several seasons, perhaps even the entire series.  I think Smallville did something close to that with Lionel Luthor, and later Lex.

Farscape and Stargate evolved into that, certainly.  Weeds had a similar thing going, with an overarcing threat to Nancy and her family, with their status quo usually falling apart in the season finale.  GLOW has kind of followed that same structure, with the story building to the finale, with a central plotline carried throughout the season.  In the first season it was about learning to perform a wrestling match, building to shooting the show pilot.  The second season was about Debbie's coping with divorce and chauvinism, as they produce their first season and deal with potential cancellation, after Ruth spurns the advances of a tv exec.  There are running subplots (more in season 1 than 2), as well, such as season 2's where Bash searches for Florian and is confronted with his own closeted sexuality.  GLOW isn't as strong an example, as the dynamic is a bit different between the first and second season; but, the central plot structure is similar.

Are comic book television shows any more formulaic than Sitcoms? Or Police/Crime/Procedural shows? Or Westerns? Or Mysteries? Pretty much any television show follows a standard formula/process. It is what "Hollywood" understands: a generic formula to follow within a 1/2 hour or 1 hour program. A set up, then a bit of foreshadowing/plot, then solving the issue and then a big finish. It is WHAT and WHO is involved during the story that is meant to entertain and enlighten. Go too far away from the formula/plan and you sometimes end up with awful or truly terrible television. Creativity and writing and acting is what makes all the difference...

Yes, I rather watch George Reeves Superman, Adam West Batman, Van Williams Green Hornet, Lynda Carter Wonder Woman, Lois and Clark New Adventures of Superman, and others that made in the 50's to the 80's over the shows that are being made in the past 5-10 years and I agree that current superhero shows are being very formulaic in design and that's bothers me a lot and I don't watch Arrow, Flash, Black Lightning, and any others at all these days because they don't do me any justice and becoming more soap opera-like that bothers me a lot. The costumes that they shows these days irks me the most ...