I like the Sale section split. It's going to be a little more work for the listers, but for the buyers, who far out number the sellers, it will make finding what you are interested in easier and more importantly, faster. It takes time to have to distinguish what is being sold in each thread.
Example: Title "Captain America and Thor for Sale" Which one? PFs? Hot Toys? Now I have to go into that post and figure it out. That wastes a ton of time as you repeat that task. Now if I go into the Sale section, I know I'm going to see what I'm looking for as a statue collector. Same for 1:6 collectors. The ones that collect both will just have to search both threads, which really won't take any longer. Browse one FS section then jump to the other. It's the same amount of content, just split into two.