Honestly, I would keep the shield back chairs, re-pad and recover, then make other changes to the room that will update and freshen the look. I know this wasn't the question, but maybe something to think about. Add a new rug with more pizazz, remove the dried stuff from the chandelier, remove the valances and the little colonial shelf, and paint a more sophisticated color.

Your chairs are beautiful..did you think about reuhphostering and when doing so, add thick padding to increase the comfort (and look). Between the fabric and the thickness, your chairs will look very different. I would use a fabric that coordinates with your captain's chair, so you could keep that as is. If interested in other ways to update your room, you could remove the valance, add art and a mirror instead of the small shelf and clock, and remove the decor around base of chandelier. Additionally, I might think about painting a soft blue to compliment your rug and perhaps use a blue/ivory damask for your chairs. [houzz=]; [houzz=]

I switched from antique wooden dining chairs to upholstered chairs (in a patterned fabric) and I'm glad I did. They are so much more comfortable, which makes lingering and socializing at the dinner table much more inviting. The contrast with the wood table and added "weight" to the chairs makes the dining area look cozier and updated. And since we pull these chairs into the living room area for extra seating when we have a lot of people over, they are much more comfortable for guests than the old chairs.

You can actually use both upholstered one for the host chair and the other for the side chairs...but I know all of your guests would prefer the upholstered one...for comfort!

I had the same dilemma. I added to upholstered chairs. I am very happy with my decision.