Do I ever!
The SDK beta was an attempt to work on this area, perhaps as far as demystifying some of this stuff. While this has yet to happen, I get the impression that Sparx expects to make real progress here. The SDK started with parts of the original documentation, and some new stuff was added from there. They also did some real cleanup on the prior verbiage.
Sometime in the most recent build or two the SDK returned as part of the main documentation, but the work goes on. Roy and his crew are making definite progress in this area, but remember that they have all the rest of the docs to work on as well, so progress is gradual.
My hope is that Sparx will eventually document how the schema is supposed to fit together. [I consider how it actually does so to be an instance, since the actual implementation will evolve as does EA.] As well, I'm hoping that some formality will be introduced on how the various text and memo fields that contain custom-formatted information work, so that we're not guessing all the time. Some of these fields clearly change over time, but that doesn't mean they cannot be documented, just that there is additional work that Sparx must do to keep EA usable by the community.
Sometime in the future we'll all have to deal with another schema. It's clear that Sparx wants to defer this 'pain' as much as possible, but the above "work" is part of the cost of doing so.
[OK, rant over for now. This is YA 0.02 CAD. Still, given the recent change in currencies, that might actually be worth something...]
David