Whoa! Crazyness! That's insane! So much too look at. Very awsome. Well, the only thing I can think of for making it look more busy is the point of view. You have a point of view that's looking down on everything, making everything look small and insignificant. It's kinda like your whole image is background. (This sounds mean, but that is the furthest from my attempted meaning) All I mean is that there is no real subject, (except for the totally awsome tower in the middle!) but even that is looked down upon. If you were to bring the camera lower, maybe tilt it, it might make everything more dynamic. Really I think that's all it is, you're looking for depth and stuff, which is hard when it's all on one ground plane. (I think you were tyring to fix this with the ships. Oh, what if you were looking at the whole scene through a cockpit window! That would really give it a foreground, rather than just a background). But really, I don't know. It's a hard one. you could just keep adding more ships, but when does it get to that "overdone" point? Maybe if you added search lights or something, reaching out into the sky, making it less 2d? Well, good luck, I can't wait to see how it turns out!