Not only is Downtown aiming to dress up the Gateway Arch grounds, but there's a long term plan to redevelop the Gateway Mall. Phase 1 was Citygarden. The rendering below is of the western half the mile long green strip in the heart of downtown St. Louis. The Civic Room of the Gateway Mall includes the Soldiers Memorial, City Hall, Peabody Opera House, Central Library, Savvis Center Arena, etc.
The Gateway Mall Project: See plans and rendering here!