[This is no longer valid in version 1.2 beta - see later answer.]
There are lots of different ways of slicing and dicing the question list, including by the number of answers that you suggest. Many of these options are planned for future versions, but if you want to sort by the number of answers now, you could also implement it fairly easily, if you're comfortable with a little PHP programming.
First, add something like this to qa-db-selects.php:
function qa_db_most_answered_qs_selectspec($voteuserid, $start, $hidden=false, $count=QA_DB_RETRIEVE_QS_AS)
{
$selectspec=qa_db_posts_basic_selectspec(true);
$selectspec['source'].=" JOIN (SELECT postid FROM ^posts WHERE type=$ ORDER BY ^posts.acount DESC LIMIT #,#) y ON ^posts.postid=y.postid";
$selectspec['arguments']=array($voteuserid, $hidden ? 'Q_HIDDEN' : 'Q', $start, $count);
$selectspec['sortdesc']='acount';
return $selectspec;
}
Second, add a case to the big switch in qa-page-hone.php by copying the 'unanswered' case, replacing qa_db_unanswered_qs_selectspec(...) with qa_db_most_answered_qs_selectspec(...), and changing other things as appropriate. You can change 'unanswered' to 'most-answers'.
Third, add a rule in the $qa_routing array in qa-index.php that maps the request 'most-answers' to QA_INCLUDE_DIR.'qa-page-home.php'
Last, add a navigation item in the big array in qa_content_prepare() in qa-index.php, again, modeled on the 'unanswered' item.
There's already an index in the database that is suitable for sorting questions by most answers, so it should be a scalable request.
