The National Coalition to Save Our Mall presented plans to expand the mall to include East Potomac Park as part of their Third Century Mall project. So basically, their plan to Save the Mall is to expand it.
East Potomac Park is really the only place in DC one can go for a good training ride. It's flat, there's little traffic and it's close to the urban core of the city. The plans do call for making bike trails and planners claim it would give cyclists a place to ride now that they've been "crowded out by museum".
Personally, I don't have trouble biking in or around the mall. And I don't see how taking away one of the best biking areas in the city will help cyclists. And I don't see how doubling the size of the mall "saves" it.
If they're really interested in saving the mall, then they should work on making it a 24 hour part of the city. When the sun goes down, the mall is dead. I'd like to see a "Tavern on the Mall" type bar/restaurant somewhere near there. And outdoor cafes. A place for residents as well as tourists.
While it’s true that the more cultural uses you plop in one location the more efficiently that location handles them, it does so at the expense of urban diversity as that location becomes ever more isolated from the rest of the living city. On the other hand, if you use cultural nodes as civic components in mixed-use neighborhoods, you enhance the experience for all.
Someone should read Jane Jacobs' The Death and Life of Great American Cities.