As the forum database gets bloated over the years with the size reaching several+ gigabytes (mainly thanks to the ubbt_POSTS table), could you introduce an "archive" feature that would allow the admin to move posts older than a chosen date into a separate table that is read-only?
That way the current, workable table would be smaller and easier to work with for greater server efficiency, whereas all older posts would be cordoned off in an archived posts table.
I've come across this when reading about features across various software and this is definitely something I would appreciate on my site.