Hello!
I would suggest the following:
1-Custom table names. This could be either during installation or through a pm or a dat file.
2-A sub board facility under a board. This hack was given somewhere here but not integrated in the routines of wwwthreads. Would be beautiful to integrate in the admin optional.
3-Ability to display Categories in different ways i.e. in two columns table and such layout flexibility. Now it is extremely hard to change anything out there.
4-File permissions correctly done when the scripts saves changes. On a shared server it is stupid that the scripts creates 644 and later the provider gets headaches to make then 755.
5-Different possibility for layouts of the threads. It is extremely difficult to change even any of the fonts while not using the css.
6-Ability to use dynamic codes while showing threads within the subjects and messages.
7-Ability to send mass emails in steps of 25 emails batch or 50 per batch with clickable links to whom to and also searchable which users to.
8-Backup the database
9-Kind of a possibility to integrate other programs for authentication for e.g. e-classifieds
But some of the above could be already in the script or discussed in the forum, I do not know.
Even without any of those above, its a great script.