Some Suggestions For The Inevitable Justice League Movie.

  I'm a big fan of the Justice League. I'm not a life-long fan nor do claim to know everything about them. I can't reference things they've done in the comics years ago or obscure characters they've ran across, which is why I tend to claim I'm a fan of superheroes, not necessarily comics. But though my fandom is relatively new, it's no less strong than other fans from the days of say, Snapper Carr(Hey look, obscure!).
 Those characters are really the only one's that keep me regularly interested in superheroes. The exception being Spiderman I guess. Otherwise, my reaction to most "capes" would be "That's kinda cool."
Their powers run the gamut from sci-fi, fantasy, mythology, realistic, to traditional superhero. So I'm pretty much covered. 
Now that I got that out of the way, let's talk a bit about the movies.

 So now that Marvel found success in The Avengers, and even before that, the idea of a Justice League movie was in the works. At one time there was a script that had the movie being all CG(If it was anything like DC Universe Online's CG trailer...I'd have been all in). But since The Avengers WAS successful, it's a pretty sure bet that Warner Brothers is going to attempt a shared movie universe. The big issue here is that WB doesn't exactly have a good track record on the big screen. On TV they've done well enough, especially in animation where they excel.
To be fair, it may not really be a bad track record, since they've really only stuck with Batman and Superman, as much as they just don't throw everything at the wall and see if it works on film.

But with Nolan's Batman finished allowing for more superhero-y takes, and Man of Steel being successful enough to warrant not only a sequel, but the first team up amongst JL members, it appears as though WB is making their move. And after Green Lantern...it ties my stomach up in knots both in excitement and worry.
Green Lantern was...a misstep.
I liked...things...about it. Heck, a lot of it was simply seeing one of my favorite characters finally get a movie. But it just didn't capture what makes the character and that universe cool. Ryan Reynolds was fine. In fact, the cast was fine. The issue was that Green Lantern should've been DC's space opera. Big and sweeping sci-fi with aliens and imagination. But what we got was just kind of a typical comic book movie that, after an embarrassingly short training session, grounded the character to Earth. And it's a shame too because Mark Strong was a great Sinestro, Ryan Reynolds did well enough and can pull off cocky, and clearly a ton of work went into designing the Corps...but since it was a flop, WB may be too afraid that it was the premise itself and not a bad script.
But enough about that, let's get into Justice League.
There's a lot of things about what they should do that I really have no opinion on such as casting or whether they should follow the Marvel pattern and set the characters up first or just jump straight into it. But here's a few things I think they need to think about:

-I'm pretty sure at this point, we all GET Batman and Superman on their own. Them teaming up first is one of the things I had in my head before the team up was even announced. I love their dynamic when they work together or even fight. Superman almost being more human than Batman, being the lawful symbol and example out in the open and Batman being a symbol of fear as a vigilante. I really hope that stuff comes through. So hopefully Zack Snyder digs into those differences in the Man of Steel sequel. Then Batman and Superman can have an existing relationship, whatever it may be, before Justice League. I don't want to have to spend more time on those two than is necessary. I get it. People love Batman. But Justice League needs to spread the love.

-First off and very simply, the tone should differ from The Avengers. I feel like this should be a no-brainer. These are vastly different characters who differ from each other in their own universe. I realize the tone may be difficult to find with characters like Batman being dark and The Flash being light, but still, effort needs to be made to differentiate from your opposition.

-They should come together on their own. No 3rd party. No Cadmus or any other organization. Is it really a big deal if this doesn't happen? I guess not. But it WB wants to separate themselves from Marvel, this subtlety could help. Make them work together because they absolutely must. Not because someone else wrangled them.

-The threat needs to be big enough. There's not much you can do here to differentiate themselves from The Avengers. An invasion type of thing is necessary. Something like Darkseid, Mongul, delve into the Green Lantern spectrum, or heck, something from the multiverse. I'm not too worried about this. They'll figure it out. But an interesting idea could be to use a storyline they've used in the comics and have a secondary threat be Batman's on paranoia and mistrust with him having all the emergency plans in case one of the members goes rogue. Or save that for another movie.

"Just come within arms reach."

-Whatever they do with Green Lantern individually, whether they reboot first or jump straight into JL, like I said, it needs to be...as much as I hate the word...epic. The scale needs to be big and sweeping. Even the Justice League threat could be Green Lantern related since some of the more recent DC universe wide crossovers have originated with the Green Lantern Corps. Just GET THIS RIGHT WB.

-As far as Wonder Woman goes, there's been several efforts to get this character back either on TV or in a movie. Before The Avengers, Joss Whedon was frustrated that WB woulddn't green light his own Wonder Woman script. Just a few years ago, NBC had a failed pilot for a new TV show(which having heard the premise, I'm kind of glad)
I've heard people say the character doesn't translate well to screen. That's a load.
If Thor worked for people, this would easily work. They just need to focus on the "Greek" mythology tone they've been using. There's precedents set for this working in the movies. And as for any controversy surrounding her costume...just for the love of God, use a hybrid of her Amazonian armor and regular costume. It's not that difficult.(I'm well aware she doesn't NEED armor. I'm compromising here)

                                                   

Current costume minus the comforter.

Something like this, minus the cape...

There have been complaints about her costume for years from people who don't even read the comics or put any effort into exposing their eyeballs to the character, despite occasional changes and explanations, yet it still falls back into a form of it's classic look. And speaking as a male who regularly visits message boards, not too many people are focusing on the ogling aspect of it. Wonder Woman is one of those characters that's hard to complain about. She's been treated respectfully throughout the years and remains a strong, independent warrior. Treat her this way on screen and it'll be fine. Contrast her warrior like nature with Superman and Batman and it'll be gold. Avoid 70's Lynda Carter stuff too. And as far as casting goes...she's an Amazon. That doesn't necessarily mean she should look like a body builder, but whoever they get better look tall and sturdy.(I'm fairly certain any suggestions for casting WW will fall on deaf ears and they'll just find some actress who too short and too thin)

Yep, his clothes come out of a ring.

-Make The Flash relatable. He's a regular guy. A cop who gains powers by accident. Green Lantern is cocky, Batman is brooding, Wonder Woman is a fighter, Cyborg is young and inexperienced, so just make The Flash the even tempered guy he is. Like the audience. Plus, I love the idea of arguably the most powerful character being just an average guy...well...average cop.
Also, get creative with his powers. You don't need to, but there seems to be a bunch of guys out there who think: "So...he just runs fast?
"He just...he JUST---?! Are you kidding me?! He moves and thinks faster than anyone...ANYONE. He could incapacitate Batman before he could finish crying "My parents!"
But I digress. With WB's plans to do a Flash spinoff from Arrow, I'm very interested in how that turns out. It'll be the first time since the terrible show in the 90's and a couple of episodes of Smallville that the character gets a chance. I'm pretty excited. Now I apologize for the crassness of the following picture...but it makes me laugh so...

Some exaggeration

 -Cyborg is the new guy in the Justice League since the New 52. If they go with the current lineup, he'll be in the movie. Look, he's a half man, half machine. I don't have much to add here.

"I'm a Cyborg!"

-And that brings me to Aquaman. I don't feel like having to keep defending him...there's no reason to. It's not the 60's anymore. All they need to do is follow Geoff John's run and they'll be fine. They can't be too delicate with the character out of fear that he'll be seen as a joke. Just use the established mythos and it'll work. He's a ruler and shouldn't feel small or like background around the likes of Batman. If there's any sort of nod toward Geoff John's work, it'll be to call attention to his reputation and destroy it.
The sad thing is, the paranoid part of me says if they just use the comic version of the character, despite being the same for a really long time, all the bros will think they're "trying too hard" to make him relevant. Well, they can kindly go screw themselves.

Honestly, that's all I've got. Whoever directs it just needs to keep the no-talent studio guys away. Let people who care about the characters like Geoff Johns, Jim Lee or even Zack Snyder do what they do and I think they'll do fine. If the studios get involved it'll probably come out like either too much of a copycat of The Avengers that it won't feel like it's own thing or it'll sidestep any inspiration the writers/director might have and just be shallow entertainment.

Humans are creative. Be inspired and get creative.