I ran into some game developers at Game Developers Conference `10 and we got to talking about game audio. I mentioned freesound and it was funny because some of them kind of groaned, then I said I was an admin here.
They mentioned some features they felt would make the site a lot easier to use, and I agree.
As I recall, the main improvements were:
1. Make it easy to search for items that only have a combination of tags, or to add tags to an existing search to narrow it down. (In freesound 1.0 I think the only way to do this that doesn't involve pasting tag id's into the php request url is by hoping that the other tag you want comes up in your search and clicking the plus button next to it?)
2. Have some sort of "quick play list" feature where you can queue up a big list of audio you want to listen to, and then play through it and skip around, downloading and/or flagging the ones you want to download.
Dunno if there is anything like this on the feature list for nightingale but I think it would merit consideration, in order to improve the experience for people looking for samples on the site.