Quite right (full disclosure: my digital gear is all in 4/3" format with lenses designed for that format), but if we folowed your advice we would lose the irony of applauding 36x24mm for giving us "full frame" while denigrating the new, larger 45x30mm Leica S system as a "crop". Maybe Leica should market it as a "super-sized DSLR format" and avoid the anachronistic term "medium format".
What's the shortest focal length lens (non fisheye) available on the Leica S2, and what field of view does it give? I believe it's the 24mm, yes?
The same focal length lens on a FF MFDB (they are available) would give a larger field of view.
You have to compare like for like from a system
So, the S2 is
a crop when comparing it to other MF systems.
The shortest (decent quality) focal length lens on the Canons is 14mm. It works just fine on both the 5D and 1D, but the 1D crops the field of view.
It makes little sense to compare the Leica to that system, because there's no lens available for it that gives the equivalent field of view.
This matters at the wide end, like I said in my original post.