Hi prongated,
First, please recall that I termed my suggestions "guidelines" not "rules". That was an intentional choice or words, as guidelines are not usually considered to be as hard and fast as rules and allow for some flexibility, which I believe is an important distinction.
To answer your question, if we want to continue to have an "anything goes" site spanning the range of the touring artist to the adult beginner who has just completed five lessons and decides to present Liszt's "La Campanella" saying it's the best he can do, but it's impossible to listen to any more than the first few measures, then we don't need any guidelines. We simply need to brace ourselves when clicking on a selection and instead of finding a gem, it turns out to be a lemon by anyone's taste.
You hit the nail on the head with the word "goal". In reference to quality, should our goal be to allow everyone to post a recording no matter how bad, or should we--as members and listeners--expect and insist on a reasonable level of musicality? That concept might seem elusive, but I know your fine playing, prongated, so if I were to ask you listen to five recordings and then tell me which ones display artistry, which is average, and which ones are terrible, you could sort them out easily! But again, it's the goal that drives the objectives and guidelines, including any addressing musicality.
I agree with you that there is a difference between a lack of musicality and the need for further practicing. There again, most professional pianists and accomplished amateurs have a good sense for that. The former, of course, involves a lack of attention, understanding or proficiency in the fundamentals of reading, interpreting and performing, while the later is more a matter of adding polish to get a piece up to recital pitch.
You raise a good point too on the matter of spamming or presenting too many recordings in one fell swoop. There again, a guideline might simply ask posters to phase in the several recordings over a few weeks to spread them out a bit out of consideration for other members. I believe that most (not all) people would be reasonable about that if 1) they read the guidelines and 2) understand the rationales or "the whys" behind them.