your making it harder for me to pick out things. I like that.
ok! *claps and rubs hands together* the first thing that stands out to me is that it still screams "I'm a 3D animation rendered out in 3ds max!" its because its to perfect. Look around at the world. Nothing is a perfect. especially a civilization under the ocean. The wood (or whatever those pillars are made of, I'm assuming they are wood because they are brown) should not be entirely visible like that. Have you ever seen a ship wreak under water? There is stuff growing all over it. It becomes a reef in a few short months. Put some Barnacles and shells growing on it. Here is an example.
notice how the fish is underneath the ledge of the piece that is sticking out? Fish LOVE to congregate underneath docks and in shipwrecks. It offers them protection. Put some fish underneath the platform.
Other than that, its pretty much good. There are a few things I would do different but you're talking way advanced stuff like Layer rendering and sky dome rigs. I love the subtle play of lights you have going on. Very nice. I would add some very weak color lights scattered through out the scene to give it some more mood. and tone down your over all light so you don't brighten the scene with extra lights. You pulled off the particles very well.