OK. I will chime in a little.
Get draperies that are really heavy, with a nice thick "texture" feel to them, and make sure that they are double layered, meaning that it is like two pieces of material sewn on the edges. Even then, you may only get the same equivalent as untreated drywall surface. Glass is SO sound reflective and transmissive (sound going through the glass.
My wife wanted glass french doors going into our theater, then I talked her down to a single door with glass panes, and then down to a single solid filled steel door. She thought that she would hate it, but loves the sound proof-ness (yup, made up that word) of it.
I would put the glass doors NOT at reflection points, still put thick draperies over them (although, why have glass doors if they are just covered anyway?), and then have your first reflection points be regular drywall that you can put some sort of acoustical panel on.
With a projector in the room, you are asking for a LOT of potential light leak and sound issues with all of that glass. Even with great draperies. Why spend the money on all of that glass if you are probably going to regret it later. Sort of like breaking a cardinal rule of an "ideal" theater room.
Now for other thoughts, I love the bass traps in all four vertical corners.
If possible, treat the entire front wall with basically one giant acoustical panel... (I can get you more details on how to do it for cheap). Doing that, with the bass traps, with F.P.R. being panels on walls (not glass with curtains) will do wonders for clean, clear sound.
As already mentioned, widen the front soundstage by moving the right and left another 50% closer to the outside walls and push them back a little - away from the seating.
Also, I would move the side surrounds *slightly* forward. In line with where the middle seat's "head" would be. You will be able to do this because you will have the glass shifted so that is drywall (
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Rear surrounds should be fine. Since they are as close to the center of the rear wall as they can be (with the door in-between), it will help to draw the surround sound further back for potentially a greater overall surround effect. I messed with this myself thinking that wider made more sense, but it has its limits. Your configuration for those two looks good. As long as the doors are closed when playing something with surround.
Your room screams for an acoustically transparent screen, however, it also has the potential for a seriously large screen and the larger the screen, the more screen gain you are going to want. Problem is that despite manufacturer claims, the best current acoustically transparent screen you can get is about 1.1 gain in real world tests. That is ok for a 104" screen, but you can go really big. Something around 2.0 gain or greater should be looked at and that means no acoustically transparent screen. You could still do a minimalist screen wall. Put the front speakers behind acoustically transparent dark panels that surround the screen. Then the whole front is really clean. It hides the speakers, bass traps, above mentioned treated front wall, etc.
Here is a link for some ideas. Obviously if you DID do an acoustically transparent screen, the center channel could go right behind the screen.
Minimalist Approach to Screen Wall Well, that's it for now. Tear up what I said above and make it fit your needs. There is always a balance between form and function and no matter what, you need to live with the room. I am just offering you some sound advice (pun intended) on the acoustical properties of "Plan 'A'"
