Hi Phil - this is an interesting question.
In absolute terms my suggestion not to import a keyword hierarchy does not hold.
It is possible that somewhere someone exactly shares my photographic interests as well as my philosophic views on the best ways to document an image.
It is generally true however that there would not be too many people who answer that description.
The issue goes far further than just having unused keywords.
The whole structure may not gel with the person trying to use it not to mention the granularity of the hierarchy.
One of the selling points for importing keyword hierarchies i the fact that one can edit it to better suit one's needs.
But this argument is rarely valid since most individuals who are importing a keyword list do so precisely because they are unwilling or unable to wrestle with the whole process of constructing their own hierarchies and so attempts to edit and restructure the imported hierarchies are usually doomed to failure.
Tony,
I am seriously considering purchase of David Riecks' Controlled Vocabulary Keyword Catalog because I have a healthy respect for the amount of time it takes to construct such a collection. Maybe I'm influenced by my wife, the corporate librarian.
There is a definite skill set to creating a usable keyword hierarchy part of which is understanding one's own needs, partly an understanding of how keyword hierarchies can be constructed (a taxonomic view of the world), and finally a good understanding of Lightroom's own keywording toolset.
None of these requirements are insurmountable by any means and once obtained why would one want to struggle with someone else half-baked keyword hierarchies when one can just do it more simply from scratch.
I don't doubt that I could construct my own keyword set, but I know from experience in such endeavors that there will be a lot of change over time, so that I might feel impelled to review older images to re-apply keywords. That could be a lot of extra work.
Possible exceptions might be something like a detailed and complete taxonomic keyword hierarchy of bird species if one is an ornithologist (amateur or professional) and one knows EXACTLY what one is getting. This would not be a full keyword hierarchy for even a bird photographer since other types of keywords would still be needed. So, again, the needs, or, assumed needs of individual photographers likely preclude any possibility of a more generalised keyword hierarchy being suitable.
This is an important point. As a railroad hobbyist (or railway enthusiast for our UK friends) I've strugged with this issue within the narrow confines of the North American and European railroads and rail transit systems. There are issues like mergers and acquisitions, official vs. common-use names, renaming, etc. Using my example, do I have a keyword "French National Railroads" or "Chemins de Fer Français" or "SNCF?" Constructing a robust taxonomy here, with synonyms and a hierarchy, this is going to be enough work that I would be just as happy to spend a reasonable amount to have this work done for me for "general" subjects. My underlying thought here is that the "best" is the "enemy" of the "good."
So, my advice is to roll up one's sleeves (metaphorically), analyze one's won needs, learn the Lightroom toolset for creating keywords, research how to group and classify keywords, and, finally build one's own keyword collection.
Tony Jay
Summing up, no doubt that I could to my own keywords, but I want to focus my efforts on my railroad hobby, my family and friends, etc. It's a philosophical point.
Maybe over time, one of the really prolific plug-in writers like John Beardsworth or David Friedl will develop a tool to analyze frequency of keywords used, and then I could strip out all the classes of keywords I will likely never use. But that's a problem for the future.
Just one additional point which has to be made in this area. For my railroad hobby photos, a general "keywords" metadata field is really inadequate. Reading up on Adobe's XMP architecture, I believe that I need custom metadata fields for rail-specific images, in combination with keywords, of course. Unfortunately, John Beardsworth and others have demonstrated to me that custom metadata fields in Lightroom are not possible because plug-in writers can't define additional XMP fields that would be in the catalog, or could be input by the user, or imported or exported. (John: please correct me if I have mis-stated here.)
Phil