The Order by selector:

<tr><td><h2>Order by</h2></td>
<td><select name="ordering"><option value="normal">normal</option>
<option value="oldview">oldview</option>
<option value="raw" selected>raw</option>
<option value="age">age</option>

has problems.

You need to say what each of them do. The only one clear is "age", and
it turns out it you need a pair, age descending, and ascending.

And add a order by bug number options, descending and ascending.
Also a way to forget about severity level barriers... pure bug number
ordering from head to toe.