how about a backsplash that just tops counter and a new huge framed out mirror?

I actually think a backsplash, though functional, will take away from purity of everything you have "floating" against the wall. I would keep everything just as you have it. I would not add a backsplash.

The room looks unfinished. I would definitely add a tall back splash and consider a full wall mirror above. I don't know enough about the lighting in the room, but you could think about a sconce for each side of the round mirror if you don't do a larger wall mirror.