Keep the current arrangement. Put a lamp or tall plant or tall sculpture in the corner as Beverly shows in her first rendering. I would not put a coat rack there; it's too far from the door and they always look messy anyway. And I would not move the chair there; it ruins your conversation grouping. You already have the right arrangement. Just put something useful or beautiful in the corner. Leaving it empty would be better than any other suggestion here.

If you are referring to area to right of tv, I would say yes, some shelving of similar finish as barn door, to the ceiling basically, would balance it; doesn't have to be very wide shelving, but the height is needed. A tall statue of some sort, a modern art sculptural piece, for example - in a dark finsh - might be interesting, too. I think my favorite idea might be to do something interesting with a plant or plants. That would bring an organic feel to the space, and would not compete with other elements. With plants, metal might be an interesting option there, also, like this piece above, from Lowes.

You have a lot of space so mirror and shelf both things can be attached. In the middle you can add the mirror and on both sides shelves will be good. Diamond shape wall mirror https://www.houzz.com/products/diamond-frameless-mirror-1-beveled-edge-with-2-hooks-22-x34-prvw-vr~44814339 Octagon shape wall mirror https://www.houzz.com/products/20-x-30-octagon-frameless-wall-mirror-bevel-polish-20x30-prvw-vr~44814518 Decorative Mirrors https://www.houzz.com/products/fab-glass-and-mirror-stylish-frame-square-wall-decorative-mirror-prvw-vr~84538948 https://www.houzz.com/products/fab-glass-and-mirror-the-rising-sun-decorative-sunburst-wall-mirror-prvw-vr~84538936 Shelf Options: https://www.houzz.com/products/corner-clear-glass-shelf-kit-6-x6-with-chrome-brackets-triangle-12x12-prvw-vr~44792982 https://www.houzz.com/products/rectangle-floating-glass-shelf-12-x-30-with-chrome-brackets-prvw-vr~110191036 https://www.houzz.com/products/bent-glass-shelf-chase-series-1-4-thick-with-brackets-prvw-vr~44814686 https://www.houzz.com/products/fab-glass-and-mirror-stylish-bathroom-bent-glass-shelf-with-chrome-brackets-cle-prvw-vr~84539026

Beverly's spot on. Get an appropriate sized rug to define you space--use ALL the space. Everything crammed up on the fireplace isn't working. I will never understand a TV in a room where no seating orientates towards watching it. There's confusion and dishonesty in those configurations. The drapes, matching the walls hung waaay too high...they are adding nothing to your space. Those divided light windows with no casings call for a different sort of window treatment, perhaps roman blinds.