The Topics View does IMO make the one forum discussion moot. If you want one forum, there it is with one click. Sadly it is one of the features I'll miss when we move the site over to a mobile-friendly set up (someday). It's odd that more forum software options don't offer it.
In this thread you've got five different ideas on how to organize the forum. When I built the thing I was the only one around, so I went with my idea. If you search for old posts a lot (I do) the sub forum structure makes it way easier.
I agree with P. It may not be perfect but it works ok.
"You just need to go at that shit wide open, hang on, and own it." —Camp