Feedback on draft review of ARIA in HTML

I've completed a review of the ARIA in HTML doc. Before I log issues, any
concerns or feedback on the comments below?  They're in the order they
appear in the document, not priority order.

Thanks!
Cynthia


   - Why can an <a> with no href take any role but <area> with no href can
   take no roles? Shouldn't these be consistent? Seems like <area role=button>
   would be useful.
   - Should <iframe> support role=dialog?
   - should <img> support role=figure?
   - Editorial: It would be more clear to explicitly say that <img> without
   alt can take aria-label and aria-labelledby. The linked document says that,
   but it's kind of confusing
   - Why can <button> be menuitemcheckbox, radio or switch, but not
   checkbox? A pressed button, a checked switch and. a checked checkbox are
   all kind of the same thing
   - The <td> spec is confusing, because <table> is listed earlier with
   only one mapping, to role=table. <table> can take any role, so I think the
   text is saying what happens when table has taken different roles. But, I
   had to scroll back and forth to the table entry to figure that out, and I'm
   still a little confused.

   role=cell <https://www.w3.org/TR/html-aria/#index-aria-cell> if the
   ancestor table element is exposed as a role=table.
   role=gridcell <https://www.w3.org/TR/html-aria/#index-aria-gridcell> if
   the ancestor table element is exposed as a role=grid or treegrid

No role if the ancestor table element has role=table, grid, or treegrid;
otherwise any role <https://www.w3.org/TR/html-aria/#dfn-any-role>.


   - Editorial: in the <tr> entry, role=row is all blue. Should "role" be
   red?
   - In 3.1, checked vs aria-checked is explained, but I'm still not sure
   I'm reading it right. Can I use aria-checked to make a tri-state html
   <checkbox>?
   - I like section 4. I find this flat table to easier to read and
   understand than the ontology-based attribute sections in the aria spec.