I could really use standard tech-docs-style section numbering, with H2 headings numbered 1, 2, 3, etc. and H3 headings numbered 1.1, 1.2., 1.3, 2.1, 2.2., 2.3, and so on.

The numbers should be in the same font/size/weight as the heading itself, with periods as the separator between numbers. I personally would be happy with just a space separating the number and the heading. Others will no doubt prefer the number and the heading to be on different indent levels.

Options probably need to exist whether to use numbering and when to stop. For example, numbering H2 and H3 but not numbering H4-H9.

The numbering would appear in the TOC and the number itself should be something that can be used in internal cross-references, as in "See section 2.3" instead of "See section 2.3. A very long heading indeed" No terminal period in referenced numbers in case we're using them mid-sentence.

Obviously, the number should auto-update as sections are added, deleted, promoted, demoted, and moved, and the references to them should auto-update as well.

You know, the usual.