Sorry guys, I just have to make a quick reply when it comes to this:
Aquaman looks a certain way. Would you accept Idris Elba as Superman just because he's talented?
Yes...
Also your acting like Atlantis is in the mid west. We have no idea what ethnicity they are. They are an alien race so it's a bit different than say The Fantastic Four.
You see... I kind of get where Airwings is coming from with this. As Batman fan, I wouldn't want Elba to play Batman, and I'd probably be very vocal about it. It has nothing to do with me being racist as people often tend to call someone just to quickly discredit any future arguments however good and within reason they might be. I am not. I simply don't like the idea of such a big ethnic change of the character that has always been caucasian. The same would go if they'd cast white actor for Cyborg. Race change for the sake of race change is pointless, forced and to me, as such, very annoying. Actually, I find it insulting. I think such an approach is very dangerous to our way of thinking. Learning to accept others is not tied to us pretending to ignore the fact that we're different when it comes to our backgrounds, but acknowledging, respecting and enjoying that very fact.
I like very much how multiethnic Justice League seems to be, and, sans Aquaman, it actually proves that it can be done without changing ethnic backgrounds of already established characters. It's a bit more vague when it comes to Wonder Woman in comics, but it is pretty much safe to assume that Amazon would not be caucasian, and Cyborg has always been black. Though, I still hope for a black character that is much more popular and more strongly related to the older Justice League (and also a much better character than goddamn Hal Jordan

) - John Stewart.
With all that being said, I think that, considering his universe and mythos, indigenous background befits Aquaman quite much. Probably much more than his caucasian comic book one, I find. And it seems to be an important aspect in the way they decided to depict Atlantis, so this definitely doesn't fall into the category of race change just for the sake of race change.
Okay, it wasn't really a quick reply, I admit. I won't prolong this argument since, like I SEE SPIDEY said, this is not the casting thread. That ship has sailed. And, if I may add, I like the direction in which it's sailing very much.