12
-needs ability to add polls
-mark all posts in all forums as "read"
-ability to set the order of forums in a category
-permissions for usergroups in private forums
-ability to hide private forums completely
-ability to attach files to posts
if there are already options like the ones above that are in a stable XOOPS release then forgive me.
Xoops is kickass! Just important to keep the forum updated and improved to keep your users using.