There is some mileage to this argument - the search box doesn't really pretend to be local-only. But for the last three releases (from when Unity was introduced), it was only a local search, and I think many users expected it to stay that way. It's also somewhat uncomfortable that the easiest way to launch an application or open a file is to do an online search.

For me, it's annoying, and I've turned it off in the settings. But it's not such a big deal that I want to fork Ubuntu, or even switch distro.