> Ok, I have added them.

> What would you think of a patch like this for core?
> https://github.com/WordPress/WordPress/blob/master/wp-includes/comment-template.php#L1826-L1841

>     $defaults = array(
>         'walker'            => null,
>         'max_depth'         => '',
>         'style'             => current_theme_supports( 'html5', 'comment-list' ) ? 'ol' : 'ul',
>         'callback'          => null,
>         'end-callback'      => null,
>         'type'              => 'all',
>         'page'              => '',
>         'per_page'          => '',
>         'avatar_size'       => 32,
>         'reverse_top_level' => null,
>         'reverse_children'  => '',
>         'format'            => current_theme_supports( 'html5', 'comment-list' ) ? 'html5' : 'xhtml',
>         'short_ping'        => current_theme_supports( 'html5', 'comment-list' ) ? true : false,
>         'echo'              => true,
>     );

I think that ship has sailed unfortunately. That is something that we should have done when we first introduced HTML5 support in 3.6. If we changed it now we would break themes that support HTML5 comment lists but not short pings.