With all due respect to TLE041's suggestion, i think it's great the way it is. I really like how the colors of the rotala wallichii blend in with the colors of the rock. Just keep the water sprite trimmed low and let everything else grow in. Maybe try something in the right back side, like blyxa aubertii or maybe even a large branchy piece of driftwood. I wouldn't do anything with the rock placement, since i think it looks great, except maybe move it all to the right a few inches if that isn't too much trouble.
I think you're dissatisfied with it because you were probably going in the direction of an iwagumi tank, which is typically more focused on the hardscape and has less stem plants in the back. It's hard to find an "in-between" style which looks so amazing when done correctly.
Regardless of what changes you do or don't make, you're on your way to a beautiful aquarium!