Why do ROC Dioceses have names based on nonexistent cities on Crimea while Greek/Antiochian/Georgian/Serbian/Romanian/Bulgarian/ROCOR Western European Dioceses have normal names? Was it in order not to annoy the EP or maybe ROCOR?
For Sorouzh, I suppose it is because of some English law which forbids non-Anglican churches to have dioceses in the same name. Evben the Roman Catholic Church does not have a diocese of London, but of Westminster...
For Korsun I have no idea. But here in Germany, there is an MP "diocese of Berlin and all Germany" - and ROCOR has one with the same name. The EP has a "Greek Orthodox Metropolia of Germany" (and three parishes under the Paris exarchate).