Hello,
maybe your right. I miss some clear rules in this case. I'm a genealogist and my ancestors are coming from this area and it would be very useful to have a bilingual map with first polish name and second the historical german name, this you can find under www.openstreetmap.de. You can find this bilingual names par example very often in Silesia. In the former polish villages of the Ukraina, they use also "osm.wiki/Tag:name:pl=...", so I think it's more used generally than "old_name". Do you live in this area?

Thank you! Your right. Are there some gravestones?