This is a fair point!

Mostly, I think that would produce an ugly API.

The reason I've been leaning towards that solution is that it assigns the responsibility of locating any other resource, in one request, with full backwards compatibility, to exactly one location, freeing other locations to change in a more fluid and graceful way without the cruft.

Edit: Oh and because other URLs can have the context of their parent paths deliver some value or information. But then again URLs should be opaque =). Definitely worth thinking more about!