What should we add to the National Mall?

The Smithsonian just released the 6 designs under consideration for the upcoming National Museum of African American History and Culture. All of the designs are decidedly modern, echoing the National Museum of the American Indian and East Wing of the National Gallery. This building, slated to open 2015, will likely be one of the last additions to the monuments and museums that already line the National Mall.
I'm excited to see how things turn out, and I hope the museum committee chooses something that will fit the dignity of the location. The slide show of options reminded me of HGTV's Designer's Challenge. Will the homeowners go with tasteful but boring, or ambitious and expensive? Will museum planners want a design that already dictate museum placement? Some architects proposed gallery names or "Door of No Return" slave ship mock-ups.

Here's my humble opinion on the slide show presentations.

1. Not bad. It wouldn't clash with the surrounding neo-classicism, but it wouldn't quite thrill either.
   
2. Ummm, this just looks silly. Like an alien structure from a children's TV show. The huge glass walls are a neat concept, but they don't mesh well with the hulking metal blob.
   
3. I like this one. The nautilus design makes a good use of space and nature, and reflects the circular Hirshorn gallery. An ascending spiral of galleries to a "Celebration" view of the monuments gives a good sense of journey. My only qualm is that this lends itself to a strict time line interpretation. Visitors might be reluctant to wander as their interests lead them. I'm also imagining a train of school kids running back down to the bottom once they've reached the end of the line.
   
4. Tasteful, with an organic feel, but also a little underwhelming. It's basically a decorated box.
   
5. What. The. Heck. Oh, I see, it's "a building made of natural materials, rising as of out of bedrock and muck," aka when Stonehenge imploded next to the Reflecting Pool. "Along one side runs a wetlands scene, a nod to historic Tiber Creek that ran through part of Washington. Its glass roof features etchings echoing Yoruba ancestral arts, and it also has an outdoor amphitheater facing Constitution Avenue." This creative-sounding description is code for "ego as huge as the stone pylons." If this were built, it would be all about the structure, not the exhibits inside it. Every aspect, from the ceiling beams to the outdoor projection screens, is in-your-face and over-the-top.
   
6. Ahhh, that's better. Dramatic but not like being pelted with boulders. The wood details are stunning, but I'm not sure how all of this would flow together. You can't just slap a ship's hull onto a rectangle. Also, I'm not sure how I feel about the very literal ship's masts at the entrance. African-American history isn't only about the slave trade.