For what you had intended, Joe, as a study of lines, shadow and texture, I kind of like it. What I found distracting were the top of the mailbox in the bottom of the frame, the slanted vertical of the front edge of the brick wall, and the dof. It may be better to shoot it with a smaller aperture so you get the entire mailbox in focus.
I can't comment on the size, since on my screen it is just right. I have a wide screen, though, so YMMV.
I would differ with the others in that I am not so concerned with the bright right third - it doesn't help much to burn it since it just turns grey and flat. You may want to reshoot it with less exposure. What I would do with this shot is burn in the shadows, to accentuate the middle third of the frame, and create more depth. I hope you don't mind - I played around with it a bit.
Why is the mailbox open?