Rephrasing myself: GNOME 3 and Unity are "oddities" we should ignore just as much as Windows 8 for those who think they're too otherwordly to be used.
The fact is people get used to anything in life, even bad interfaces. Windows 8 will be a sales success by being force fed to computer buyers. GNOME 3 will not have such backing, so its adoption rate will be a lot slower. But the point is that people have choice, and people will eventually find what's best to them. GNOME 3 seems to be despised by a lot of people because of its defaults and lack of choice. So GNOME 3 has plugins. Nice. But people in general settle for the defaults and expect a given set of options. If the defaults are unuseable (to many) and to recover the expected functionality you'll have to thinker so people will run miles from it.
UIs should be unobtrusive, because people use programs to do things. People don't need UIs to stare at them (Windows 8) or fiddle with its innards to get to the basics. The'yre not an end per se, but an enabler to let people get things done. If it stays in the middle of what people want to do people will use something else that lets them do what they want. Dead simple. One can shove years of methinksuishouldbelikethis and other theoretical, dadaistic designers' ideas because people like aesthetics, but don't live by it. Did you use Windows 8's message app? Good aesthetics, almost zero functionality, perfect for a Hollywhood movie but terrible for daily use.
About typing an app's name to open it, KDE SC, Windows, GNOME, OS X, all have it. It's a staple now. KDE even extrapolates it with its idea of "semantic desktop", but WTF Nepomuk (also used by GNOME) is not agreed by all.
In fact, sadly I have to say that functionality/usability-wise, according to my view, it's Windows 7, OS X, KDE on top, GNOME 2 and others at the middle and GNOME 3, UNITY and Windows 8 at the bottom.