You’re creating a false analogy between a province named by the British Colonials and named after geographic coordinates - Pakhtunkhwa was an historical name for the area. Unlike Karachi which already has a historic name. Besides KP was a name change issue not a “new” province.
As for creating new provinces based on ethnicity – I am opposed to that, whether its “breaking up” Punjab into three provinces or creating a Karachi province. If we need to create new provinces, they should be done on an administrative basis. Speaking creating new province EVEN ON administrative basis - can anyone prove that they are more effective? I’d like to see an article or two.