I put openings through walls all the time. Maybe 12 inches wide or so. Add a shelf or two. If that's what you mean by narrow then I'm all for it. Line of sight is very important. The further you can see through the house... including through these openings, the house just feels bigger.

Not sure where you wanted to put the banquette but it could be interesting.

a free standing table and chairs would be more flexible.

will sound be an issue? what was the original intent with the slats? feature? privacy?

wondering if there is another option, less permanent?

Paul F Could you share examples?

Theatre rooms need to be dark for viewing and IMO the separation is a great way to control the amount of light and you already have a large opening so not sure what the purpose would be . Hang some huge art on that wall instaed .

I agree with Patricia that it is not a good idea. I don't think it serves any purpose, especially with the large cased opening.