Feature Request: option to use the TOC as excerpt

I put some working code on the previously mentioned topic. I’ll paste it here also.

/**
 * Substitute a Table of Contents for the excerpt if there are more than 2 headings.
 */
function my_excerpt_TOC ( $text, $num_words, $more, $original_text ) {
  $many = preg_match_all( "/(<(h[\w]+)[^>]*>)(.*)(<\/\\2>)/", $original_text, $matches, PREG_SET_ORDER );
  $out = '';
  if ( $many > 2 ) {
    foreach ($matches as $val) {
      $level = intval( ltrim( $val[2], 'h' ) );
      if ( isset( $save ) ) {
        $out .= ( $save > $level ) ? '</li>' . str_repeat( '</ul></li>', $save-$level ) 
          : ( ( $save < $level ) ? str_repeat( '<ul>', $level-$save ) : '</li>' );
      }
      else $first = $level;
      $save = $level;
      $out .=  '<li>' . $val[3];
    }
    return '<ul>' . $out . '</li>' . str_repeat( '</ul></li>', $level-$first ) . '</ul>';
  }
  return $text;
}
add_filter( 'wp_trim_words', 'my_excerpt_TOC', 11, 4 );