Update: After looking at all the suggestions here and chatting with my wife, we decided to set the room up as though we're going to get a sectional (which we are, once the dust settles on the cost of getting a new house). It doesn't do much, but it shifts the chairs and couch slightly left, and it shifts the whole front stage left, with the L main being across the entryway. I realized that by doing this, I'd a) get a wider sound stage, b) be able to move my eventual MLP to the left a bit, and c) not have a jumbled wall of LCR/tv/console. Also, it gives me the possibility of moving the LS back to either her desk or the wall on the other side of the room. So far, it already sounds much better, just more "open." I angled the RS more toward the left side of the eventual MLP, and while it's still not as good as I've had in wider setups, it's much better than it was. Also, to circle back to suggestions of repositioning everything, we deliberated a lot on whether or not to move the tv and C channel over the fireplace, but we both agreed; it just didn't "feel" as good as our current layout, both aesthetically and physically. Plus, as my wife pointed out, the current setup gives us the option of getting a bigger tv or projector/screen. Right now, it's a 65", and it looks great, but at some point a 77" would be really nice.
So now that we've improved things a bit, what would you guys suggest on placement of these Atmos speakers? According to B&W, they're supposed to fire at a fixed 45 degrees, so I'm assuming they'd need to be moved slightly inward and closer to the eventual MLP. Is this correct? What's the minimum distance from the wall? I've seen everything from 18-24" to .1-.3 the width of the room to 3 ft (what the B&W tech support told me, though I don't trust that necessarily). I've also seen folks cite Anthony Grimani's notion that ceiling speakers should be between the mains and the center channel. I guess in the end, I've never had that top layer before, so I don't really even know its purpose. Is it primarily to add a sense of sound from above (which would supposedly mean slightly narrow is better), or is it supposed to help with left/right pan effect (which would supposedly mean wider is better)?
Thanks again for all of the suggestions. And here's a pic to give the update. And don't worry; our future sectional will be more of a chase lounge on the left side, so there won't be a sofa arm in the way.