Okay, I'll play:
-Assassin's Creed ("okay, we all know that fans are far more invested in historical assassin stuff than the modern day stuff, so let's make a movie that almost entirely takes place in the modern day. Genius!")
-Continuum (this would take more than a few lines to explain, so I'll try and put it this way - Continuum had great potential, and it's clear that the writers were really trying, but it just doesn't reach its goals. It's sci-fi that really wants to have a message behind it, but doesn't really pull it off. I'll always have a soft spot for Continuum, but at the end of the day, it just doesn't pull its goals off.)
-Batman v Superman (like above, I can see what this movie was trying to do, it just doesn't pull it off)
-Doom (like, I don't know if this would have solved much, but you could have started by making the monsters actual demons; that might have helped)
-Dune (you're taking one of the best sci-fi novels ever written, and you deliver, well, this. Christ, I hope Villenhue does it justice)
-Harry Potter (the movies. I don't know if they could have pulled it off, but the movies miss so much from the books to the point that certain plot points no longer make sense in the movies, or are inverted in their meaning)
-Independence Day: Resurgence (at the core of this film is an interesting premise - what would happen if aliens invaded in 1996, and as such, human society was rapidly changed in that it was united and had access to advanced technology. This film's answer is "they'd make cool guns," and proceeds to rehash the previous film. I know this was always going to be an action movie, but Christ, you could have tried to explore this idea a bit further.)
-The Lion King (the live-action remake. Now, I've got a pretty dim view of Disney's recent live-action remakes, Jungle Book being the exception, but it occurred to me after seeing this is that there's actually a case to remake this film. Namely, to have the story better tie-in with Simba's Pride, because that film requires us to believe that the likes of Zira and Scar's loyalists were always there, we just never saw them. So, remaking the first film and including these elements? That could work. However, it doesn't do anything of the sort. It's just so...safe. Frankly, I kind of hate this film, but it's a film that arguably had potential.)
-Merlin (this is a bit debatable, because if you asked me what sunk Merlin for me, it was the ending (fuck. The. Ending.), but even then, elements of rot did set in earlier, in that there's only so many times Camelot can be taken over before the people should ask whether the House of Pendragon is all it's cracked up to be. I'm including it here because I feel if Merlin had come out to Arthur earlier, the story could have accomodated new storylines that would show Arthur in the process of uniting Albion. You might argue that that's veering too close to the King Arthur story we're all already familiar with, but it's a story that resonates in our minds for a reason. Honestly, I loved Merlin initially, and I think it could have been much better towards the end than it ended up being.)
-Prisoner Zero (I'm running out of time here, but suffice to say, Prisoner Zero is an excercise in wasted potential. Where you're presented with two key plot points, and it focuses on the wrong one throughout its first season (and likely only season, because we can't have nice things).
-Saga of Seven Suns (yes, I'm including books here, bite me. Basically, Saga of Seven Suns is a case of solid worldbuilding marred by lacklustre writing, both in its moment-to-moment text, and lack of character depth. I'll give Anderson credit for creating the setting itself, but it really needed better characters inhabiting it.)
-Sonic Underground (this is debatable, but I'll put it this way. Sonic isn't a series that I go to for in-depth storytelling, but it's still a series that has done the angle of "freedom fighters against the big bad" well - Archie comics, STC comics, SatAM, etc. Underground technically does this as well, but has the twist that Robotnik can only rule because of collaborators - the aristocracy, while the commoners are left to suffer. That, at the least, is different from the other scenarios I mentioned. Unfortunately, Sonic Underground was too focused on the boy band aspect, and this plot point of potential moral ambiguity only comes up once, maybe twice, out of 40 episodes. SU is my least favourite Sonic cartoon, but I think it could have been better than it was.)
-Star Wars Sequel & Prequel Trilogies (you know why)
-Prometheus (a film that shot for the stars, and instead blew up in the launch phase.)
Legend of Korra in general was a whole potential waste. Not helping matters was Nicklodeon basically threatning cancel the show after every season. The ending of Season 1 being the biggest complaint of deus ex machina. Where Korra gets all of her powers back with the biggest ass pull ever. How cool and more meaningful would have been for Korra to get each and every one of her elements back in each season.
This.
Also, I'll extend the DEM to her unlocking airbending. Throughout the season, we see Korra training in airbending, namely how to avoid contact (e.g. the airbending puzzle), but she unlocks it by just...punching a lot. In-universe, that makes no sense. And storytelling-wise, it undercuts any character development the moment might have imparted. FFS, you had a template with TLA, as firebending and earthbending are hard for Aang because they run counter to his personality, but they couldn't even get that right.
