Currently, ocean biomes are totally useless other, than squids, and immensly aggrivating to deal with. Why not give them purpose? Seabed Temples will not only make traveling ocean biomes more interesting, but will also supply sponge to single-player without cheats or mods. I don't know about you but i'd rather search for Temples in the ocean rather than complain about how there's nothing to see in the ocean.
Far left: Zoom out of temple
Far right: Top of temple
Center: Main room