Recently we learned that Darkseid is in talks to be the main villain in the JLA movie. And while Darkseid IS often portrayed as the main villain for our league of justice, many fans aren't happy with this rumor. Most fans feel that Darkseid is too similar to Thanos, the speculated villain for the Avengers sequel. Some people think Darkseid requires more build up, or should be saved for the 2nd or 3rd JLA movie. And I'm here to say that I agree. I'm also here to suggest another villain, called the Anti-Monitor.
Although generally considered a villain of the Green Lanterns, the Anti-Monitor made his most popular appearance in the pages of the Justice League's 1985 limited series, Crisis on Infinite Earths. This was a very famous arc, considering the amount of DC characters that were killed during it (including the infamous death of Barry Allen, the second Flash).
The Anti-Monitor himself, is a being billions of year old. Along with unlimited cosmic powers, he holds the ability to devour entire universes. And that's where the Justice League comes in.
As for what he could give to the movie:
He's Different
The main problem people have with Darkseid, is that the Avengers could be facing off against Thanos,
who is arguably a direct copy of Darkseid. And while Darkseid came first in the comics, Thanos came first on the big screen. Darkseid would also offer an alien invasion, something we already saw in The Avengers.
Anti-Monitor doesn't want to be your supreme ruler, he doesn't even want to rule the universe. All he wants is to eat you, for the cosmic power.
He Shows Just How Powerful The Justice League Are
Say what you want, but the Avengers and Justice League are nothing alike. The Justice League can almost be considered gods, in their respective universe. We've seen the Avengers face off against one god, but imagine seeing the JLA face off against someone with the power of 3 gods.
It Establishes The DC Universe
If the 2011 Green Lantern film is non-canon with the JLA movie, the Green Lantern Corps will need to be reintroduced into the universe, and what better way, than with a Green Lantern villain? The Crisis on Infinite Earths story line featured an ample amount of DC universe characters. And while many of these characters might not fit into the film, major ones CAN be introduced.
So these are my thoughts on who the villain should be in the Justice League movie. Leave a comment with your own thoughts, but remember to be respectful.