I have been in a discussion about whether or not places that are officially cities should be tagged as cities even with a population of 40 000 and lower.
My idea is that if you don't tag them city, you adding false date to OSM. And that the renderers should use the population tag to decide how large and on what zoom level a name should be placed.
An other thing about places where there seems to be a disagreement is on what should be tagged, villages/cities... or municipalities.
My idea here is that it should be villages/cities and that municipalities should be areas as they contain more than one village.
osm.wiki/index.php/Talk:WikiProject_Belgium/Conventions/Places
Discussion