Looking over it over the last few days. Some good stuff in there.. if beyond my experience!
Ideally, if this job is done right, people will be able to make a robust plugin without needing to understand so much of what's under the hood.
Anyway, I don't much understand the web-engine plugins, nor how they fit into the rest of the infrastructure - this is the area where your expertise may be the most valuable.
Don't forget to chime in on the Lightroom Plugin Development site over at Assembla too...