I took the liberty to create the Divergent transitions - a primer - General - The Stan Forums permalink, currently pointing to Divergent transitions - a primer, if anyone wanted to followup on this, but the discussion is probably far from done, although it has mostly faded away (e.g. at Discourse - issue/question triage and need for a FAQ)
I also agree with @betanalpha about the important role of pedagogy and user expectation (though probably not about how to address those best). I still think linking to an overview + collection of additional resources is the best we can currently do.
I think that the only potentially really dangerous recommendations that were mentioned are those concerning priors where there is a real risk of biasing the results substantially. I think that all the other recommendations floating around only pose the risk of wasting the user’s time. I agree being very careful in wording the prior advice is warranted.