@Zangelbert Bingledack I agree. The Economics subforum was originally further down on the index page, but we temporarily moved it into "Trending" to give the 'Gold' thread a head start. Now that the Economics subforum has its regular readership, we can probably move it back.
You're also spot on about topics. Ideally, distinct topics should be discussed in separate, newly created threads. We sort of keep replying to the 'Gold' thread by inertia and because that's where the action's taking place, but it would be hugely beneficial for the forum if we created as many new threads as possible.
One benefit of having lots of different threads would be, as you mention, to encourage new members to participate and to give people who are intimidated by long threads something to read.
The other, equally important consideration, is that Google doesn't care much about multi-page threads because its algorithm is not capable of indexing them properly. When deciding whether to index a page in its search results, Google's spiders analyze the page's title (which on this forum is always "Thread Title - Bitcoin Forum"), metadata, and content, and then Google presents it to users whose search queries its considers relevant. This analysis is impossible for threads that span dozens of pages, so most of the posts beyond the first few pages are completely lost to search engine traffic, which of course is a darn shame because our discussions are of such high quality.
Our search engine traffic (and hence new member signups) would probably multiply by 10-20x if we posted more evenly throughout the forum.