Your room's modes:
Not too bad (according to modeling). I am assuming the speakers face is 1'11" from the front wall and 3' from the side walls. In this setup you have a null at 54.5hz which the SW will/should correct.
Try bringing L/R away from the front wall 2' 11"(to 3') to the face of the speaker and see if you like it better. Don't worry too much about maintaining the same distance (to the listening position) as that of the center channel. Not such a big deal and you will gain quite a bit of soundstage.
You can play with the position of the subwoofer. It is not ideal but if it doesn't feel right to you, I would put in on the sidewall at "1'11" or 5'9 from the front wall.
here it is a 5'9". You remove replace the null at 54 with one at 46 albeit not as deep and reduced the null at 80!.
These are all suggestions but let your ears (and WAF) make the final determination.
If you are aiming for music listening, I would suggest something different. Hope this helps.