Need help on my 80g cube aquascape

[reef tank 2.0]

The more I stare at my aquascape, the more I think I need "something" in the middle of the tank. I have the caves and pass through at the bottom but nothing above that. My initial thought was to leave the mid to upper area completely open for the swimmers of the tank. As well as the corals that could possibly get larger and larger. That would be enough to let it be.

But the other side of me sees an open playing field that is desperately crying for attention.

I don't want to add rock that end up making it look like a blob or rock wall. But I also don't want to go up much higher due to swimming space needed.

I don't know though....what are your thoughts. I turned off my blues, so here's some photos if what I have going. The tank is 24" deep

 

[reef tank 2.0]

and I will add this, my par meter readings at top of the rock you see in the picture are about 250-300. with almost 100 at the sides/corners. the light is 11" above the water surface. I don;t know if I will ever get anything that requires intense lighting, but I don't think I want to limit myself if I ever change my mind. adding high rock structure would give me more par range for that intense light that some corals need.