The system wasn't "designed" per se, it *developed* over time.

Over the years there have been various attempts made to "simplify" or otherwise try to come up with a system that someone thought made "more sense" but every single attempt has met with dismal failure.

My use of the term, "developed" up there might better be defined as, "evolved"...

Not sure what the fellow meant with the W and B stuff up there, neither makes any sense to me. Apparently he is going off of the idea that the white keys must represent a specific desirable place to center things. That is not necessarily the case here at all IMO. Ever meet a Black Key Pianist? Hmmmm...

--Mac