Lousyreeds, this is also a similar situation to what I face. A smaller room, with not a lot of absorption, and a lot of hard surfaces.
We'll presume you were able to site the system as it was prevesiously, in the happier times...
Your speakers look to be in a pretty good position in being out from the front wall from my eyeball, but I will tell you that if you measure more carefully than I can via your pictures, you may want to move the speakers out a bit more into the room. Following the Audio Physic speaker positioning guide helped me significantly even if the amount of space needed to get my speakers where they recommended seems small. For the full text, you can look it up on Stereophile's website, under Jonathan Scull's old column, Fine Tunes. Title may be "Loudspeaker Positioning, Part 1". Somewhere in the 2000 - 2001 area, I think.
Quickly, the gist is that there are areas that kill bass and areas that make it as good as it can be. Halfway out into the room is best, but is impractical for most people. A quarter of the way is the next best position, and works for a lot of us, including me. Your room setup supports this brilliantly as well. Next, you want to be a quarter of the ways out from the sidewalls as well. The absolute no - no is to be a third of the way out, from either the front or sidewalls. These positions are bass killers, and will shift the overall feel of the system towards the mids and highs, something we need to be most vigilant about in this situation.
In my own experience, doing this required pretty small movements, but resulted in more significant improvement than I would have ever believed. I was along the 1/3 lines from the sidewalls, and gained a lot. Hats off to AP for sharing this with the audiophile world.
The other thing is that rather than toeing your speakers in more, you should try the opposite. I would predict with a pretty high degree of certainty that if you pointed the speakers straight ahead, a significant amount of brightness would vanish. Right now, the tweeters are possibly aiming right at your ears, and the presence region is hardwired into your brain.
Still, I most certainly do NOT recommend placing speakers this way, as imaging is also destroyed. Very good or better than that soundstaging, once experienced, can never be replaced. Whenever I toe speakers in, I get rewarded with that panoramic soundstage that I will simply not be without. Pointing the speakers straight ahead drives me crazy. I just wanted you to give it a shot to see if we can confirm that it is not the system that is the culprit.
The means to solve the problems, in my opinion, are to address the room.
If you have the extra foam you have said, for fun, try covering the four corners in the room where the two walls and the ceiling comes together. The quick and dirty way is to simply mimic the triangular Room Tunes method of covering the corner with one piece of foam turned caddycorner. If it moves things in the positive direction, you can investigate using a different configuration to cover up these areas.
To my ears, this is a nasty place where a lot of reflection occurs, and as we all know how sound travels, it's going to be the upper mids and treble frequencies which can move the most freely. As such, a lot of brightness and harshness occurs in these instances, especially, in smaller rooms. My own low intelligence puts forth that since more of these frequencies are added into the mixture, the overall balance of the sound is thrown off in the fatiguing direction.
Of course, your experience may be quite different, but I think given the abundance of foam, time, and the desire to settle the sound down, it's at least worth a quick try.
If this happens to help, you can also treat the other areas that Room Tunes addresses, where the four walls come together (though I think the doorway nixes one of those to be treated), and the front and back wall to ceiling interface.
Lastly, while I understand moving the listening chair out into the room is not an option, and this presents no problem, a bit of absorption on the wall behind the listening chair is also high on the list of things to try. Simply put a piece of foam there as well.
I do believe in the adage that a room too live is preferable to one too dead. You can always quiet things down, and my opinion of music needing to be full of life and vibrancy dictates that a bit of sparkle and jump factor is mandatory.
