The threads in all the forums are displayed based on their updated time. Some times few unanswered threads are moved out of the first page due to this. This makes them remains unanswered until otherwise a user has interest to move to the next page. But these threads should have more priority as the latest answered threads. Here is a simple suggestion to resolve this.
Every forum can have two lists of threads,
The first list has answered threads sorted on updated date
The second list has the list of unanswered threads
This arrangement would make more sense since it will display both unanswered thread as well as latest updated threads.
Please incorporate this if it is feasible.
Thanks,
James.