If the movie were to be animated/CGI/etc, what if they did it like A Scanner Darkly? That would be cool.
I personally do not want to see Tom Welling in this film. It's a big "**** you" to Brandon Routh, and it's a bad idea. Audiences would get confused at why they didn't cast Routh. From the look of things, it looks like they might make the JLA movie something like the "young" JLA from Smallville (Superman, Green Arrow, Aquaman, Flash, Cyborg), but that would suck.
These are the JLA-ers that we must have:
Superman
Batman
Wonder Woman
Green Lantern
Flash
Green Arrow is optional. Martian Manhunter is a possibility I guess, maybe he could be the focus of the sequel. I'd like to see Darkseid as the main villain of this film.