I agree with your desire to see PSU continue to succeed, and also that - particularly for new users (or at least those that like to turn to a manual) improved documentation would help. I'm sure that even the reassurance that a 'manual' exists would help to sell the product to some, even if it's rarely or never used.
If your idea was to go forward, then a wiki would be an obvious candidate, and wikifying the existing 'quick manuals' would be a good launch point. However I do rather doubt that there would be enough people to make it happen on a volunteer basis - and to manage / police it. I doubt, for example, that I'd have spare time to contribute anything useful.
On a positive note, though, we do have an exceptionally good forum here, offering helpful and rapid advice, which is surely a big plus for anyone moving to PSU.
I think you concerns about "management" are very important. We can't kick off such a project unless we are all satisfied as users that we can make it work. And we will need Hert's support, if only to host the wiki. And we might need him to do a "quality check" on wiki contents, which could be a time commitment.
While a forum is definitely a resource, it could scare away potential users who see "all the dirty laundry being aired." Better is a manual that can be downloaded as part of the 30-day trial. However, the forum, including past posts that provide answers, could be a great source of first-draft content for a wiki that could be converted periodically into a manual.
I am just getting started with Photo Supreme and right now I'm working out all the details of how to integrate Photo Supreme with Lightoom for my existing images. Eventually all new images will enter my workflow through Photo Supreme and then Lightroom would ingest the images+XMPs. FYI, most of my images are Nikon NEF, but some, including iPhone pictures, are JPG-only. I could imagine that once I have all that down (and I have a multi-page test plan), I could document that in a section called, "Working with Lightoom."
I suspect that as I work through this Lightroom integration process, I will have some questions for the forum. Or I may discover some "hidden" capabilities in PSU that solve my problem. Real-life example: All my images in Lightroom have their original file names as generated by the camera. I want to organize them into folders based on date: yyyy\mm\dd and rename each file to yyyymmdd-nnnn-SUBJECT nnnn is a sequence number within that date.
The issue is that the XMP sidecar file contains the name of the NEF main file. So if I use PSU to rename the NEFs, are the XMPs also renamed? This is just an example. I do know that PSU has some amazing features that good, or even adequate documentation would unlock.