Your tank looks nice. If you want to rescape, you can add a few more red plants. OR split the 3 reddish plants you have in different sections (Left, Center, Right).
You could also get some stones/driftwood occupy the dark space in the back.
Ultimately it's your tank, but I think it looks great.
When things are nice & green, I try to leave it alone. I'm always afraid of turning plants brown with too much rearranging/tinkering.
If you're looking for more suggestions on types of plants. Post your water parameters.