I found an interesting little feature of sorts - if you use the search tool you can a handy thread preview before clicking, so you have a bit more of an idea of what the thread is about than just the title, however this view isn't available normally just looking at the boards, except it is:
If you make a search for an underscore, it seems Flarum doesn't quite know what to do, so instead just shows the latest posts, you can then navigate to each tag and the view remains. I don't know if anyone finds this useful or prefers it over the default view, so that's my next question.
Does anyone prefer to have a preview of a thread before clicking on it? Or not?
What does everyone think the optimal content to be displayed is?
I'll update this thread later on with an idea or two of mine, and possibly I'll make a mock up of a hybrid with a bit less padding and better use of the space.