Speaker upgrade to a large room

Thank you for the inputs and advice . Unfortunately I cannot improve much the acoustics of the room except from maybe covering the wall behind the equipment with acoustic panel covered with decorative wood slats that I saw online (not sure how good they are) . The rest of the walls are either glass or full with art pieces . The open room size is approximately 1500 SF plus it opens up to a large kitchen (520 SF) . I wonder if the TWIN  12” REL SUBS will be sufficient or should I go for twin 17” new SVS subs . 
should I get the bigger  Alexx and then see if the room still needs the subs ? Thank you ,

@jetset 

You may want to ask on WBF (What’s Best Forum) who have more experience with costlier gear like your proposed Alex/Alexia.  Also, maybe reach out to Wilson Audio.

First. Beautiful system and room. 

If it was my system I would work on improving the venue. I am sure it can be done tastefully with acoustic panels and large throw rugs. Sorry to keep asking for more, but views of all angles of the whole room would be helpful. But before I invested in bigger speaker and or more subwoofers I would see how much improvement you can get. 

Often if the room is not dampened enough then you end up turning up the volume to reach a satisfying level. With high ceilings and an undampened room you could end up overloading it. 

Also, given the other equipment I'd probably improve the streamer first. But, not the question you asked. 

I hope this is helpful.

https://speakerchoices.com

You need to post the photo somewhere online and link to it. Or post it under your system photos

How about electrostatic speakers?

Here is a photo of my system. I can fit the 2 new subs on the outside of each main speaker .

It would be really helpful to see your system as it is today. There is a place to create a virtual system with photos and to identify your components under your user ID. This would really help making recommendations .