Well, we did get a nicer and larger capitol building out of it. It has a mix of modern and classical architecture in it, and there is more room to adjust the size of the House of Representatives.
President Hillary Clinton's attempt to increase the size of the House of Representatives following the 2010 Census almost worked, but it lacked support. I'm sure that without the destruction, something like that would have never been tried.
I like though how they kept parts of the ruins up as part of the memorial, the shelled out House of Representatives chamber they have in D.C. really hit me hard when I visited it, and the new capitol a little further East of the original site really gives it an emotional feel.