I am an AV integration consultant. I am currently working with a residential customer on their sound requirements for a refurbished living space and they have shown a personal interest in your 5.1 Playbar setup.
Having looked into this I'm afraid that I just cannot recommend this product to them at this time. It's a real shame as Sonos has always made great products in the past and I feel with this one you have dropped the ball somewhat. How can I recommend a setup that costs £1500+ that is not truly 5.1 without a specific TV or extra switching equipment and even then there would still be no support for DTS audio from Blu-Ray players.
I have always loved Sonos. I have specified it to customers for their multi room audio requirements in the past on numerous occasions. With this particular product I just feel dissappointed by Sonos. I think they have let themselves and more importantly, a lot of customers down.
With all that being said. What is to be done about this Sonos? How will you redeem yourself from such a short fall. The answer in my opinion is simple. Stop. Just stop making this product right now. Shelve it, bin it or whatever and get back to the drawing board. Your customers will respect you if you hold your hands up and say "We messed up here and we're going to put it right". Come back with a truly amazing product. One that warrants to wear the Sonos logo.
I appreciate that Sonos has always been about music coupled with great sound but in my opinion, if you want to enter the home theatre market and do it properly, there is just no getting away from HDMI. You have to do it. Don't do a half job, make it great. Multiple HDMI 2.0 inputs so it supports true 4K when it arrives. Do 4K upscaling on the HDMI output. Give it at least 5x HDMI inputs. A typical setup in the UK would be a Sky TV box, Apple TV, Blu-Ray player and maybe a games console. So 4 ports would suffice but giving an extra port will make customers happy in the knowledge they can add another device later. HDMI output to support ARC for customers who want to use their TV's built in tuner and streaming apps. A few optical inputs for instances where its needed that can be assigned to the available sources. A nice on-screen GUI for setup/volume feedback and even the standard Sonos music functionality.
I hope you will take this onboard. I think there is a lot of faith that needs to be restored. I want Sonos to be great, but I'm afraid in the meantime, for surround sound requirements I will be pushing my customers towards other solutions on the market.