While I love the theoretical tidiness of your idea, I don't know how feasible it is to implement. Having that many subforums will quickly become a giant tree with too many branches and only a few leaves on each. The reviews were never limited to WSC Vendors, which means anyone can post a review about any business s/he had dealings with. Since users cannot create subforums, the first person to write a review for XYZ Business would have to get a moderator to create a sub forum in which the newly mentioned business review would go.
While the current melting pot is messy, it's not impossible to find reviews of a particular business by using the advanced search option:
1. First, click on "search" in the menu at the top left corner of this site.
2. Then, change parameters
* to whatever you want, to narrow it down (or not).
3. In order to deselect everything in one swell foop, scroll down and
first check, then un-check "Check all":
4. Scroll back up and check the subforum "Vendor Reviews" to search in only that subforum:
5. Click Search, and get results:
*If you wanted the most recent posts, you can change "Most relevant results first" in step 2 to "Most recent topics first"