What The Boy Scout said about different colored lanterns. Green and Yellow are enough, the rest are over doing it.
Great Lake Avengers.
Blue Marvel. Superman is enough, pseudo-Supermen don't need to be adapted.
Shi'ar empire, at least not in an X-Men movie, especially not in an X-Men movie.
Majority of the mutants.
Howard the Duck. That duck has a human girlfriend, I don't want that bestiality on screen, it was a mistake to be made.
Spider-Man. Sure, he's a money bank, but his origin is silly and overdone. As nice as it is to see him in action on the big screen, and as much as I'd love to see Mysterio done justice on the big screen, he does not need any film.
Any of the multitude of Spider-Women. Jessica's story is interesting, if they do a Spider-Woman maybe she'd be good, but none of the rest.
None of the Robins or Batgirls. Oracle maybe, and maybe Nightwing, but not the kiddie sidekicks in tights.
Symbiotes. They suck, and I already said Spider-Man doesn't deserve a movie, at least not any more than he already has.
Teenage Mutant Ninja Turtles. I enjoy all 6 films (one of them is not theatrical), previous endeavors proved they are not big screen material.
Spawn, or anything related to him.
That's some strong views there dude.
Just to change the question slightly, which of those do you think would work on TV, rather than the movies?
I can sort of see what you mean with Superman.....because Hancock wasn't a bad film, but felt really redundant. I don't know much about Blue Marvel and if he could carry a film.
I suppose Superman had over 40 years of mythology built up before his first screen appearance, which probably helped (and being the first super-hero character).
Superman is probably the one character who has managed to work well both as a movie and TV character (in fact, if you look at the last 30 years, there aren't many long spells where Superman isn't in the cinema or on TV)
I disagree with you on Spider Man, I loved the Raimi films - and though overall TASM was a bit of a disappointment I thought Garfield really started to capture Peter Parker's character, not a bad film, just not a great one.
I think Spidey would also work well on the small screen, as villains like Mysterio would work better on the smaller scale that TV provides.
I would prefer the X-men as a TV series, perhaps then they wouldn't feel the need to kill off and resurrect characters. Also, Xmen carries the problem of having literally a cast of hundreds (or even thousands) of mutants, which is not conducive to great films
- before people start saying, "wouldn't it be great if every superhero and supervillain showed up at once and fought" I would point out how well massive battles involving confusing action between hordes of unidentifiable combatants work in the transformers films.......oh wait, they don't ! Even in Avengers, it's 5-6 characters fighting an army and Loki, which is much easier to follow and get emotionally invested in. Once in a while a big massive slugfest can be impressive in comics, but is pretty hard to pull off on the big screen. I didn't think that Singer's DOFP's final battle had much in the way of tension (that's between the mutants and the sentinel army) which is odd despite lots of well loved characters dying gruesome deaths - but the interaction between Mystique, Magneto, Xavier and Wolverine worked really well.
Also, what made Xmen a great book to read, when I was growing up, was the feeling of family. The relationships and attachments the characters had for each other. Now that is something that I feel is sorely lacking in the films, but would be great on TV.
I agree with the comment about the other Lantern corps (Red, Indigo, Blue.....) I used to love GL, but after a while that all got a bit too much for me. Sinestro corps war was great, but the whole Blackest night thing was a bit too much. (mind you, multiple corps might work in the context of an ongoing tv show, but would be waayyyy too much for a film).
Okay, sorry that's all getting off topic. Back to the original question.
the one character I think would be most difficult to adapt, and possibly shouldn't be is
Morpheus (as in Gaiman's Sandman), just because the stories are so sprawling and bizarre (and wonderful) that you couldn't capture them all - even in a TV show.
Maybe the Sandman should remain on the page (and in our dreams).
Similarly, I think Gaiman's
Lucifer is best left in print - again because the story is just so vast and the scale so immense, that it would be too difficult to do justice.
Just IMO.