Can you paint the risers or spindles white (same color as mopboard)? Or swap out the spindles? Try out the lighter riser color by putting some paper on the risers to get a feel for the effect.

There are a few options...depending on how much you want to change them. Adding a runner, painting the treads white, painting the spindles or a combination of all three. If you take a look at "dark wood staircases with runners" in Houzz pictures, you may get a feel what you are leaning towards and also runner styles. You could also add wall molding, which would look lovely as well.

Kylemore Model Home "Oakley" · More Info

classic stairs with panelling · More Info

the stairs look great, I wouldn't paint them as you will be adding maintenance to something maintenance free right now that looks great as is. Change up your wall color. If you want to add the carpet runner in a coordinating color that will change the look too. Think you will see big difference with a different wall color and artwork or frame feature wall...

How about painting the treads and hand rail black and the rest white? It is a great classical look, that will add beauty and value to your home.

Crisp Architects · More Info

What a beautiful blank canvas! Recently Blogger "Designer Trapped in a Lawyer's Body" retread her stairs with our NuStair system, the end result was nothing short of awesome. The addition of paint really adds some dimension, check out what Tasha did, I think something similar would be beautiful on your stairs!

Blogger: Designer Trapped in a Lawyer's Body's Stunning Staircase Transformation · More Info

A wall sculpture that doesn't lie flat, or try an interesting paint treatment.

Wallace K. Harrison Estate · More Info

Dana Frieling · More Info

Can you post a wider pic of the space?