I think we have something here - there is a dual nature to this beast! And yes, sexist as it may sound, apparently the male vision sees things a bit differently as far as areas of primary concentration etc (I can't wait to see the jokes pour in on this one) - but that aside, it seems like so:
1) Human field of vision
2) How much visual information are we comfortable looking at, and therefore, like looking at.

It seems those two have distinctly different answers - and perhaps the old 50mm was some sort of compromise? I still tell you this - walk around looking through a WA lens and you will get dizzy! All of a sudden, you are not just seeing but being forced to register ALL of that huge field of vision (and barrels and pins etc ). So that can't be it. Try it with a short tele (85, 100, 135) and you will feel like you have tunnel vision - even though it will probably match what you would want in apicture... I think that makes it more complicated than simple calcualtions of field of vision, angles, etc.

Personally, right now this human's perpective is getting blurry because I need sleep - what lens is that ??