Proposals about outline algorithms

[carnoxen]

• <main> is the "main" sectioning root. It would be good for its role and visually designing main contents (for instance, using css grid).
• <header>, <aside>, <footer>, and <nav> are additional sectioning roots. These can have sectioning content.
• Other flow elements are nonsense to have <h#> because it is useless or already have one comparable to that (like <legend>, <caption> etc.).
• <section>, and <article> remain sectioning content.
• One sectioning [root | content], one child heading. (1)
• Remove <hgroup>.
• Optional: define role="subheading" (original idea from Steve Faulkner) and maybe reconsider <h>.

(1)

<!-- this make sense -->
<section>
    <h1></h1>
    <section>
        <h1></h1>
    </section>
    .........
</section>

<!-- this is nonsense -->
<section>
    <h1></h1>
    <h1></h1>(x)
    .........
</section>

[carnoxen]

role="subheading" will be used like this:

<h1>title <span role="subheading">and subtitle</span></h1>

and it can be multiplied in one heading element like this:

<h1>title<br>
<span role="subheading">and subtitle</span><br>
<span role="subheading">and subtitle</span><br>
...</h1>

[MDivakarPal]

I want to work on this issue. Can I work please.