The bigger problem is that the area is dominated by parking. I am looking forward to a new regime in Congress -- I don't care which party -- that simply dispenses with all the permit-only, on-street reserved parking around the Capitol complex. There are enough underground spaces for all Members and Senators, with a lot to spare for very senior staff. The rest of congressional staffers can pay for commercial parking, take metro, or walk or bike to work. Most, in fact, already do this; the on-street permit-only parking does create additional reserved space, but not nearly enough to put more than a small dent in the problem. Get rid of it and landscape the freed space appropriately.
I understand that the Smithsonian is considering scrapping the Haupt Gardens in front of the Castle, replacing the formal, 19th century gardens (perfect in that space) with a more open, lawn-like landscaping designed to accommodate expanded underground space. Bad idea all around. This is what happens when an institution does a top-down review, with expensive architects and landscape designers who think they have to recommend dramatic changes in order to justify their price tags. You end up with change for the sake of change, with excellent and much-loved historical solutions being thrown away simply because some hired gun wants to "make his mark."
I’d enjoy the Haupt Gardens if they’d allow dogs... instead my pups and I walk from Independence to the Mall through the pathway between the Arts & Industries building and the Hirshhorn. It’s actually quite lovely.
To my mind the only space that needs improvement along the Mall is Constitution Gardens (well, that and destroying the awful WWII Memorial...). But of course they’d turn it into some post-modern monstrosity if given the chance.