Nice planted tank. I would move the big piece of driftwood to one side or the other instead of having it smack in the center. That would be an easy fix to change it a bit and give it a more natural look IMO. Nothing in nature is symetrical.
if you look at it from the front it's not actually in the center. the part that goe's up the right left hand side is placed to 1.6180 the lenghth of the tank! this is the calculation people use to place thier center piece! it meant to give that perfect nateral off center look!