Just a few ideas for forum improvements.
Being able to mark a topic as resolved is nice. Maybe a customized search could be created or option added to existing search "search for only resolved threads" to help people find solutions.
Unanswered threads - Also similar to that idea is you could also offer a quick link or way to show a search for only unresolved threads or topics with no reply. Current I dont think there is an easy way to do this. Its a common feature in forum ui because it helps people who are there to help find threads faster they think they can assist with by scanning the list of topics.
Also I have seen a lot of sites adopting the ability to highlight a particular post as 'the answer'.