That is actually a great movie you have playing in your head and good idea for Aquaman.
My biggest problem with Aquaman is the forced story that comes with him in a movie and catering some aquadic theme to make his contributions meaningful. Historically he is a bad character and the public in general does not like him. Very forgetful outside of the humor he generates mostly.
Green Lantern is too grandiose to me and he draws in such a big load of story with the rings, the core and that whole lore. The power ring in general is stupid IMO with "whatever you can imagine the ring creates" it looks visually weak on screen and its just too much for this round for a JL movie. Plus when your weakness is wood or the color yellow...... well finish the sentence.
The JL movie can be very successful with Supes, Batman, Wonder Woman and Flash. If they wanted to squeeze in Green Arrow, fine, we dealt with Hawkeye so whats one more grounded archer to roll out a 5 person team. These 5 characters are very believable and can work in the world I believe Goyer/Snyder/Nolan are shooting for. Else this movie is going to be way to big in scale and concept and make for a blockbuster bust. I can explain the Flash, wonder woman and Green Arrow in minutes, they are pretty known ( Flash is fast, WW is strong and has a lasso of truth, Green Arrow shoots arrows well). Gotta draw the line with aliens and super races somewhere and I think it is maxing out with "frickin laser beams
" else no one outside of Superman can have a fight in the game. Strength is relative, but the two I called out (GL and Aquaman) are just bad, bad characters that require kit glove care writing good stories including them on the team. If anyone loves these guys my intention is not to tread on your heroes, but they just do not appeal to the masses and would bring the movie down in my opinion.
We'll know the casting soon if this frantic pace keeps up as they would have to announce the cast by the end of 2013 Q1 2014 at the latest to hit a 2015 JL movie.