I would take the small pieces down and perhaps place a large piece on the wall you see behind the sofa. You've got a whole lot going on in this area. If it were mine, I would take everything down, edit to what I absolutely love, and reposition one thing at a time. Open space is okay and doesn't always need to be filled.

Instead of small photos and shelves on such a big wall, I think a "feature" wall of graphic wallpaper or painting design would look fab. Not exactly this print, but something like this. But, to complement your furniture and design style. You can move the current shelves to the other wall for a collage of photo shelves at eye level.

Wall hung items should be centered 5' above the floor or hung 5" above a piece of furniture. The furniture under them should be 25% wider than the hung item. The wall behind an item should be at least 25% wider than the item. That translates to: the picture doesn't work there. It loses all its presence when crowded like that.

@Ann Marie Thanks for the suggestion! I will look there. I'm a little partial to painted art rather than photography, but I'll see what they have. @lindac92 That sounds like good advice! How would the need for a lamp change what art would go in that space? I have no idea how to think about that at all. But you're right, probably I would want a table lamp there. I know from browsing around that sometimes art just goes behind a lamp, which honestly feels weird to me, but maybe it's fine. But I'm not sure how that changes what I would want to put on the wall there. @threers Thanks for the advice! I can assure you that I will most definitely only get art I love. If I'm going to look at it every day, it had better make me happy! But I would also like it to match the rest of the room if I can possibly arrange it. :) @Patricia Colwell I actually was originally thinking of having two couches (which I think may have the result of another comment of yours in another thread), but the problem is that I can't seem to make it work with our TV placement. I definitely want a couch to face the TV, and then the only real arrangement that works is to have an L-shaped arrangement. And if I'm going to have that, well, I have always liked couches with corners, so that's how I arrived at a sectional. But I'm open to other alternatives - I just don't know of any good ones. :)