I love using this space for family pics all in the same frame but different sized mats like a gallery wall and I usually put in track light to highlight the photos and a rug would be a good addition.

I have a 12' runner in my hallway with 3 large canvas prints of my kids going down the hall. It's simple, doesn't overcrowd & it adds a personal touch.

I would add more lighting with scones. If it was brighter it would look larger. Then, between scones, add in a family photo wall with simple thin frames with large light matting. A hallway runner that is shorter than the length of the hall will also help to shorten the feel of the space.

Hope this helps!

No wall too small for art! Search long narrow hallway and you'll get lots of ideas!

Mirrors, but just on one side of the wall.

Art, but just on one side of the wall.

Some inspiration

I am jealous. I've always wanted a long hallway with hardwood floors, just like yours. Instead of using family photos (put those in a bedroom or family room) what about LARGE fabulously framed or canvas prints (3 or 4 each on each wall). Either minimalist style primer colors or beautiful warm traditional style. And have a New York or San Francisco loft ambiance.

The issue is that it is very narrow. I'm ordinarily not one for wallpaper but in your case, something subtle can add interest and break up the expanse.

I would like to see a runner. I would have one made from a remnant so that you can to a custom length and width.