thanks for the pics, just a couple of comments.
Dude, you must have tons of reflections in that room. I don't see any floor or wall items to help break up the reflections.
I would recommend some nice throw rugs on the floor to help with first reflections on the floor. If you don't want to look into other treatment panels for the walls, plants, and other furntiture or wall hangings will help.
The other thing is the way you have your surrounds and rear speakers placed. It appears they are all along the back wall? If possible I would recommend placing the left/right speakers on the side walls or on stands to the side. do you have wall mounting options?