Try to put up the largest mirror you can. Some people would even make the wall a solid mirror or glue on a mirror square wall. But, if this is too involved hang a gigantic mirror. It will open up the space like adding a window. Then, put a buffet in front of it. You want believe the difference a mirror will make! (G)o to Google Images and look up mirrors or mirrored walls for ideas.

I like the idea of a piece of furniture for storing China/linens. Also, it would be nice to have counter space for putting serving dishes before family meals. I really dont need any additional light in this west facing room. Therefore, I would prefer to hang something else, not a mirror, above the furniture piece. I think it would be weird to walk in look into the dinimg room and see yourself in a mirror.

Does anyone have ideas on furniture color/style that they think would work with existing table and chairs? Carpet will be replaced with diagonal porcelain tile eventually.

Using the photo below as inspiration: a narrow bureau to hold linens in the same wood as your DR table, topped with an art. Add a a green ceramic art piece to the bureau top or 1-2 green ceramic lamps.