Certainly Martin, I believe you can tidy England categories, but it needs an approach established, adopted by all and applied uniformly. What we have now is to say the least, "random".
For England, and indeed Wales, Scotland & Nothern Ireland, I believe you create the main categories of Counties that formed the early local government and usually the source of historical genealogy records. Towns/Parish's within these Counties form sub-categories. Plus incidentals. Whilst Wikitree is a "family history" site, we should of course recognise the modern places. By relating these modern places to the historical base, you creat the source reference, and both its historical and modern geography. In future years when local government changes occur, which no doubt they will, this principle ensures a continuity to both geography and history.
Take your reference to Camden, London (The modern) & Camden, Middlesex (The older). Both exist, and both should be sub categories of Middlesex. Neither categorised as Greater London. Indeed Greater London should be explained whilst emphasied that it's not a sub-category of England.
I am not saying it will be easy to tidy England but with a team of volunteers, I believe it can be done. Some England Counties have sponsors, and if we all work on the same premise, this is a basis of achieving the objective.
Frankly England Surnames & England Names Studies are two unnecessary categories, which we are now stuck with but need to be managed the best we can. Probably make them sub categories of England.
I have added the foregoing as both a comment & answer.