Either put the set of doors you have already in the center, take the two windows out. You can either center the door and add two stationary long length windows to the sides, so you can have a wall of glass.Or get a whole new door and double the size. With the slider in the middle.. see which costs less to do. The shutters and all other treatments will hide the view. You can always when you are done with changing the doors around add other window treatments. I have some more ideas on this for you.

Should I take the curtains across the wall for balance or does it matter that the windows only span the left half of that wall? Thinking it through, I guess going across the wall would only look right when the curtains or blinds were closed. Some pattern would be fine as long as they aren't competing with any focal point. We have an L-shaped sectional which faces the television and also faces a set of built-in shelves with some decorative pieces on them Because the room is basically neutral I change the pillows on the sectional and rearrange accent pieces on the shelves when I want a different color scheme.

We have same scenario as well. In the end we decided to replace the slider with a new slider -- same size. I loved the idea of window with awning style windows on the bottom... but I decided with our narrow cat walk that it was a hazard to have them open on the outside as someone would walk into them accidentally and they would be low enough to easily overlook that they are open. I also considered removing this section of cat walk, but decided that it was the strong horizontal that lends character and period style to the house and so we kept the catwalk. One other consideration that we worked into the thought process, was if we had removed this section of cat walk it would allow more light into the downstairs rooms. Light is precious in our house, as the property is heavily treed. But in the end, for our house we choose to go with a replacement sliding door, and the steel cable system for railings so we can better see the view from inside and to keep the catwalk. Also renewed with new decking.

Unless you have a big budget, I'd just make the window larger by lowering the window sill. Then, install a French style, all glass patio door instead of the patio door that looks like a front door. Since you have the FP in the corner and the door on the left, you'll need remove the door and reframe and sheetrock the interior and patch the exterior, center the new French door, relocate electrical and your heat/air vent. Big bucks involved in making that change.