I agree, more plants. At this point all you really have to scape with is the wood. Since this is an El Natural setup, I would imagine you would want some hardier plants in there such as some crypts and anbubias, and then dwarf sags for foreground plants. Once you get more plants in, you then can remove the plant background.
Another note, is to smooth out the soil, so that it slopes down from the back to the front. This will enhance the depth of your tank and also make things look a bit more tidy.
As it stands, it looks good, but there's definately things to work out to highlight the fantastic wood pieces.
-John N.