Well, the problem only really exists when you start to self-plagiarize and fill in spaces that were already previously occupied. It's the Lich King but not really the Lich King, it's the Scourge but not really the Scourge, it's a Death Knight but not really a Death Knight, it's Frostmourne but not really Frostmourne etc.
These things were established in the past and they were well liked. All they do now is leech off of the aesthetics of these things while disassociating them from their meaning within the setting.