Wide stairs and flooring dilemma in a split level

[Colleen F.]

So what would you do with these stairs and flooring for resale?    

So this is a split level with a sunken entrance and the builder did not put in an 84 inch tread.  The treads are $110 each and the risers about $45 so I know doing the steps with carpet is likely cheaper. Is it worth it to put the treads? What about just do risers and a runner since the upper steps likely need to stay carpeted. Would you replace or refinish parquet. The landing below is tile.  This is in New England.