Based on clues dropped in the terrible Batman v Superman: Dawn of Justice, here's how I think the Justice League movie will go:
- Darkseid and his minions will invade Earth. Luckily Batman will have gathered the Justice League to fight them off, saving the day but only after tremendous destruction and vast loss of life.
- During the battle Lois Lane's life will be endangered. Any one of the League members could save her, but Batman reluctantly orders them to focus on the fight against Darkseid. As a result, Lois dies tragically.
- Superman comes back to life just in time to turn the tide and help the Justice League defeat the bad guys. But he finds a world in ruins, and with Lois dead, he becomes unhinged.
- Superman sets himself up as a dictator, saying the universe is too dangerous for freedom (or some such nonsense) and that only he can take care of humans.
- Batman sends the Flash back in time to warn his younger self, which we see in Batman v Superman when the Flash's apparition tells Bruce Wayne "Lois is the key! You were right to fear him!"
- The movie ends with Batman and the Flash and maybe Cyborg forming an underground resistance, with Wonder Woman and Aquaman returning to their respective homes, withdrawing from messed-up human civilization.
- In a cliffhanger ending, Superman and his stormtroopers rule the world with an iron fist, for its own good.
Naturally, Zack Snyder will promote this character assassination as unexpected, edgy and bold, saying no one could have expected such a dramatic reversal of expectations (except any one of a zillion comic fans who've already put these pieces together).
I hope this doesn't actually happen. But it seems pretty obvious given the dream sequences.
You know what would actually be bold and unexpected? If they're going to continue making movies in this genre, make a movie where the good guy doesn't fight the bad guy. Just have the hero (or heroine) save people from disasters, muggings, accidents and so on, and show how the demands on his time make it difficult to live an ordinary life - but show that it's all worth it, don't make it dour and depressing. Comic books were huge in the mid-20th century because they were, above all, fun - which doesn't necessarily mean simple or unsophisticated.
Or serve up something like Dredd, which has a simple, linear plot, but one that's executed with believable world-building, style and intelligence.
Or just go back to any one of hundreds of legitimately great comic stories in the medium's decades-long history and adapt it faithfully. Think how bananas it would be to watch a film based on the Composite Superman story...