Personally, I would:
1. Either:
(a) Put wall tiling and floor tiling together, and probably in Plumbing.
or
(b) Put wall tiling and floor tiling together, and create a new forum "Bathrooms and tiling".
2. Create a new forum "Groundwork and Drainage".
3. Create a new forum aimed to answering questions about qualifications, licences, memberships, Part P, legal opinions, and all the other nonsense that distracts from technical points in the main fora.
3. Work out a way to easily copy, when desired, a topic to a Wiki, and be able to edit out anything irrelevant.
4. Make the speelcacker run automatically, for every post, before it can be submitted. All of them. Every single one.
5. Somehow give the Wiki more prominence in the fora.
6. Make the search utility work.