it’s just my instinct that you won’t get any improvement by moving the speakers to the middle. However 2,5’ from the wall is not much. With your room dimensions I would keep them 3.5 feet from the side and 4.5 feet from the back walls. This is from my experimenting with placement, and again, instinct. There are real experts here, I am not.
Listening position/speaker position
I had a friend visit this weekend for some extended listening. I generally trust some of his suggestions, and his hearing may be better than mine, but I am 61 and don't have any hearing "issues." Also, in the interest of full disclosure, my friend and I are competitive with each other so there is always the possibility that he is busting on me.
I am very happy with my setup and my sound----the room is quiet, the system is quiet and I have low distortion, plenty of punch and volume, without sacrificing any detail. I have Revel 228be speakers, a McIntosh MC312 amp, C53 preamp, Pass XP-17 phono stage, Technics SL1200G TT run with an AT-art9xi MCC.
Anyway, my listening room is approximately 26' x 15' with less than 8-foot ceilings, plaster walls, wall to wall carpeting, lots of cushy furniture, and it's perfectly rectangular. I have my Revel 228's positioned on the narrow end of the room, a couple feet from the side wall and about 2-1/2 feet from the back wall. The listening position is about 10 feet from the speakers, or just shy of the midpoint of the room. My critical friend was suggesting that by having the speakers at one end of the room, I am asking them to "fill" a 26-foot room, despite the listening position being near midpoint depth. He suggested that I put the speakers in the middle of the room and move the listening position against the wall, so that the speakers are only tasked with filling half of the room. He also implied that I was under-powered with the MC312 which doesn't sound valid..
Obviously, the only way to know if I would get sound improvement would be to swap sides in the room, but his suggestion sounded so odd that I thought some of you with more experience might have an opinion.