Unity has HUD and a smart engine to find commands. And i think Ubuntu need dekstop search engine by default such as Kerry Beagle, tracker, Google Desktop Search, Nepomuk, and etc. for company Unity as a new desktop environment.
Unity needs it, i think. And everybody will be happy if they could find a document contains their name from 1 million document in desktop he forget about its filename. It will be a new innovation after Unity. i think.
And it will be advanced if the new Unity Desktop Search (or Ubuntu Desktop Search) can index files such as PDF, ODT, PNG (metadata), MP3 (metadata), HTML, PHP, and provide fast searching like Google Desktop.