I don’t think it matters one bit to help imaging or necessary. Sure any placement changes can affect sound and imaging but that can be for good or bad, and depends on the room and what is already in it. It could make it better, it could make it worse, it could do nothing. Personally I think it’s best to absorb and break up those sound waves and not have them come back and muck up the direct sound from the speakers. Even without equipment there I think it needs some absorbing panels there on the back wall for the best sound. Some people even like to place a big sound absorbing panel right down the middle and said it really helps. Which I could totally see helping to keep the sound from bouncing a million times between the speakers and walls. I wouldn’t like the look though. I really like curtains over panels on the back wall to help absorb sound and reflections and look good and get that holographic sound and soundstage. Usually with the best sounding and imaging rooms and systems you’ll always at least see some bass traps in place of the missing gear. I believe isolating the sound of each speaker to each ear is best. Think of headphones, they have amazing world class imaging, and what is between them? Our big giant heads.
But with that said ’visually’ it does greatly improve the entire space and image soundstage in that it’s uncluttered and the affect it so much nicer to ’see’. Having a nice open area allows instruments, singers, and sounds to take their place on stage and travel visually unimpeded. There is something about having a big open space and sound floating there that allows it to vsually have a more 3D depth to it. Much like if there is a back wall very close it may still sound the same and image the same, but the wall can give it more of a flatter visual feel and you have to focus your attention more to grasp it. And I do think the best overall ultimate experience is to have the speakers far into the room and nothing between them. Nice and open. My favorite rooms are like that. And eventually what I will be doing. But right now even how my system is I’m getting holographic sound better than I’ve heard in bigger room and much better gear and more open rooms. But it’s still not quite the same experience or effect with gear and a big TV there and a back wall close. But dang it sure goes very deep and 3D.
And yeah I would never ever run interconnects long like that. I cringe when I see people do that. I’ve heard some pretty horrid sound degrading from long interconnects. It can become way to much resistance for that thin wire that is in them. Me personally when I go to a bigger room I’m going to have the back wall further back, then hide the TV behind a curtain, and have the other gear very low to the ground, so I can not have long interconnects and keep the speaker wire shorter too. But still keep the stage area very open.