I see that the Twentyten has added a few aria role.
It will be very nice (and very important) if we can add "role" attribute directly in the array.
Take wp nav menu for example, it adds a div to the container, and if no 'container_id' is called, it defaults to whatever menu name is.
<div id="container-id">
<ul class="menu">
<li>xxx</li>
</ul>
</div>
A 'role' attribute can be added to the div to reduce a redundant div :
<div id="container-id" role="menu">
Right now there is no way to do it but this:
<div role="menu">
<div id="container-id">
<ul class="menu">
<li>xxx</li>
</ul>
</div>
</div>
Not pretty, not nice, ugly, very bad!