I can nominate:
-Aliens: Okay, here's the thing with the first three Alien films...you could end the series at any one of them. Alien doesn't need a sequel, Aliens doesn't need a sequel, Alien 3 doesn't need a sequel, Resurrection doesn't need a sequel. That said, of the four, I think ending at Alien 3 would be the most appropriate.
Now, I don't deny that may be unpopular, but I've always considered Alien 3 to be criminally underrated, at least based on the Assembly Cut. And like I said, you could have ended it earlier and not lost anything. Still, I feel the first three films form a nice trilogy, with each film having a different 'essence,' and each film being executed quite well, even if Alien and Aliens are notably better than Alien 3. But Resurrection doesn't quite fit this arc. Not in terms of time period, not in terms of protagonist, not in term of themes. So, I don't think the Alien universe had to end at 3, but for me, Alien 3 did a nice job of closing out Ripley's story. She goes from innocent space trucker (Alien), to badass space warrior (Aliens) to war-weary leader (Alien 3). Like I said, I'm more charitable to Alien 3 than most, but IMO, Resurrection isn't needed in the arc in question.
-Avatar (movie): I really like this movie, even if others don't, but as a pre-emptive entry, I don't think sequels are needed.
-Diablo III: Mixed thoughts about this, because I can't claim that there was no plot hook to follow after the very ending. Thing is, yes, I like D3, and quite like the ending cinematic of the vanilla game. Since that point in time, circumstances on Sanctuary have gone from bad to worse, reinforcing that Sanctuary is indeed a shithole for average joe, and any bright spots are doomed to fade.
Which I can't deny is thematically appropriate, but still, I'd have been content storywise if the story did indeed end with the promise of a new dawn.
-Firefly: The film Serenity. As in, I'm not fond of the sequel comics that followed, or at least, 'Leaves on the Wind', what with the introduction of characters like Kalista (bleh), and the promise of a new rebellion forming. IMO, the film was a perfect way to cap off the series.
-Golden Sun: Not one of the most egregious examples, because I can't deny that The Lost Age did have some plot points that could be followed up, namely Alex and Anemos. Then came Dark Dawn, which introduces completely new plot points, draws out Alex's arc even further, and has left the series on a cliffhanger. So, yeah - narrative-wise, I think the series should have ended in the second installment.
-Halo: Should have ended with Halo: Reach, as it served not only as a good prequel to Combat Evolved, but also an excellent book-end for the series as a whole. Then came Halo 4 and...sigh...
-Harry Potter: Cursed Child isn't needed. It's not bad per se, but it doesn't really add anything to the overall story, and if anything, detracts from it (one word - "Delphi." Gah.)
-Mass Effect: Okay, only played the first Mass Effect, but it strikes me that Andromeda would have been better served as a new IP. However, this is still one of the least egregious examples on the list.
-My Little Pony: Specifically the Equestria Girls series, namely 'Legend of Everfree'. This would be a long post explaining why, but the short version is that the fourth film doesn't really fit in with the rest of the series, at least under the premise that films 1-3 are really Sunset's story, not Twilight's, while the fourth film is just...there.
Also arguably Friendship is Magic should have ended with season 5, but really, that's the kind of show that can go on ad infinitum, as the status quo generally remains in place, even if there's distinct continuity.
-Pirates of the Caribbean: Well, on that note:
twistedmic said:
This might be a minority opinion, but Pirates of the Caribbean should have been a single, stand alone movie. The sequels were mere shadows of the original.
I don't think that's as unpopular as you think it is. Still, far as I'm concerned, the films go 1>2>3>4. I'd be happy for just one film, but by film 4, it really became clear that the series should have ended with the third installment.
-Pokemon: Jesus Christ, just end it already, or at least shift protagonist. Ash will never catch them all, he'll never become a Pokemon master, he'll never age, he'll never experience character development, he'll never hook up with anyone, I mean...gah!
-Red vs. Blue: I'd like to nominate two points to end the series - season 5, or season 8. Season 5 was a fine ending, while season 6 is, IMO, the show's best season. Unfortunately, seasons 7 and 8 were a bit lackustre, but ending them there would have spared us from Freelancer. So, season 5, or season 8.
-Resident Evil: Resident Evil 5. It felt like a good conclusion to the series as a whole, even if there were other plot points that could be followed up.
-The Simpsons: Come on, you let Futurama go out with dignity.
-Sonic the Hedgehog: Not necessarily the games, but rather the comic series. Namely:
**Archie: Should have ended at issue 125 or issue 50, I'm mixed. Issue 125 if it ended happily and not with a cliffhanger. If not, Issue 50 would have been perfect, since it had Robotnik's defeat, Sonic and Sally hook up, etc. The only reason that 50 isn't definitive is that some of the series's best issues came between issues 75 and 125, but after 125, something went...off. Maybe it's because I got older, maybe it was the art style, maybe it was the tonal inconsistancies that started popping up, but either way, one of those two.
**Fleetaway: Okay, technically it did end at issue 184, but did they have to drag it out? I know there's a continuation, but thematically, I felt the series ended when it had to.
-StarCraft: Namely, Legacy of the Void...maybe. Okay, Nova Covert Ops was fun, Evolution was good, in as much that it introduced a lot of new concepts (e.g. the adostra), so it remains to be seen whether the series should have ended at LotV. But, honestly, after LotV, I felt the series ended perfectly.
-Star Wars: Return of the Jedi. Okay, fine, I'm sure good EU works came out afterwards, but seriously, who watched the end of the film and asked for a sequel? I'm not saying Star Wars as a concept should have ended, but, well, TFA does undo a lot of what RotJ accomplished, basically resetting the status quo, so I ask again, who asked for this?
-Terminator: Terminator 2. I won't deny I like Salvation and Genisys, the latter of which can be seen as a bookender to the series (which would be another discussion entirely), but I won't deny that the series peaked at this point. It's made all the worse by Terminator 3, which...sigh...
-The Walking Dead: I'm mixed about this, but I'd like to submit the idea that maybe the TV series should have ended at season 3. Now, this is a long story, but I feel it needs explanation.
Of the five series I've seen, it goes 3>4>1>2>5, so while 4 is a good season, seasons 1-3 form a natural arc in my eyes. Season 1 serves as an introduction to this new world, and it cements at the end of how the group are truly on their own (end of the CDC, last vestiges of civilization, etc. Season 2 is based around the group trying to recapture their old lives (the farm), only to end with failure, and Rick turning for the darker. Season 3, for me, has great thematic inverse between Rick and the Governor - both people who were good, were pushed to the brink, who do terrible things, both look out for their own, and both collide. Come the end, the Governor's been defeated, but even after all that's occurred, Rick does let his humanity come through (at this point being more humane than Carl), lets the people of Woodbury into the prison), and, at this point in time, has a secure location at said prison, not to mention that by this time, he's recovered from Lori's death. Taking season 3 as a hypothetical ending, we have a recovery from the darkness of the end of season 2, and an overall optimistic view on the future. That in the end, it's humanity (as in, being humane) that pulls through. Nice, simple arc.
Now, ending at season 3 would have cost us season 4, but come season 5...yeah. And maybe my ideal ending is too optimistic for the setting, but, well, there you go.