FWIW, while I too would like to hear what you think can be changed or improved by the use of room treatments, I think that the photos of your set up suggest (to me anyway) that one of your problems may be related to side wall reflections which might just be cured by toeing in your speakers until the axis of your speakers cross in front of the listeners chair.
I might also mentioned that the rooms dimensions could easily cause substantial nodes/nulls which could be avoided to some degree by careful speaker and listening position changes. You might consider getting a SPL meter and a frequency test disc which will help you identify the nulls and nodes which need to be addressed.
I might also mentioned that the rooms dimensions could easily cause substantial nodes/nulls which could be avoided to some degree by careful speaker and listening position changes. You might consider getting a SPL meter and a frequency test disc which will help you identify the nulls and nodes which need to be addressed.