If true, this is a very good move. Instead of Aquaman, they could add Hawkman/Hawkgirl.
WB should really test the waters first and do research regarding Aquaman's popularity before putting him out there.
Aquaman has been written as the defacto leader, but he ain't that in the non comic book fans eyes. AC should get at least a cameo and or a movie once the movie succeeds. An Aquaman movie with Black Manta would be awesome.
Or maybe the impending alien invasion leads to a Throne of Atlantis storyline in the sequel. Atlanteans attack!