Model clarity

[stuartpb]

Looking at all the stuff that #134 and #135 and #136 got caught up on and danced around, I think there should maybe be an issue talking about the higher driving design principles of the schema here.

(Okay, really, I just wanted to have something cool for #150.)

The general ontology the schema seems to be settling into is that aspects of involvement (ie. username, password, email - things that a use case is more likely to want as a whole) take precedence over aspects of observation (ie. it's password.usability and email.usability and not usability.password and usability.email).

This rather harkens back to the #50 Call for Use Cases.

[stuartpb]

Cool things about doing it this way: this makes it so, if / when these sub-properties need to diverge, it's less weird-looking, since a bunch of heterogenous aspects are put together in repeating fashion, rather than a bunch of homogenous aspects contrasting next to each other.

[stuartpb]

Closing this in favor of opws/opws-guidelines#3.