My experience is that pretty much all Wikimedians care about quality, though some have different, even diametrically opposed views as to what quality means and which things are cosmetic or crucial.
My experience of the sadly dormant
death anomaly project was that people react positively to being told "here is a list of anomalies on your language wikipedia" especially if those anomalies are relatively serious. My experience of edits on many different languages is that wikipedians appreciate someone who improves articles, even if you don't speak their language. Dismissing any of our thousand wikis as a "black box" is I think less helpful.
One of the great opportunities of Wikidata is to do the sort of data driven anomaly finding that we pioneered with the death anomalies report. But we always need to remember that there are cultural difference between wikis, and not just in such things as the age at which we assume people are dead. Diplomacy is a useful skill in cross wiki work.