Explicit indications of a structural role are now there. What is missing, if there is no structural navigation, is the ability to have effective control over what they see. I looked at vendors to support jumping to headers. I think that checkpoint 7.6 includes too much. Need to be a manageable number of chunks for a quick overview.
Top view is the most important.
The user agents should be able to find a table of contents and tell you that there is one. My solution would be to skip the sub-tree. It could be DOM-based. MAPS could be used to contain the table of contents. But Mozilla will not now render this.