Hmm.. I'd say move the plants on the right to the back and move up the wood so its visible.
so you think adding some rocks to the right side where the crypts are? any suggestions on sizes.. or type?Left side looks good.
Need some rock or wood to create a graduation up to the crypts. In nature you have low plants and tall plants.
For background I like to use fabric. For many choices and easy to change. Just tape it on with gorilla tape. I found putting a T8 under counter strip behind the tank brings out the natural color.