There has been an interesting discussion on the Autocat mailing list over the last two weeks (well it's died down now, but I haven't gotten around to writing about it yet...) with the subject "The inadequacies of subject headings." The discussion has centered on a few posters questioning whether the LCSH-style focus on precoordinated headings is really a good idea. Several posters proposed (not all by name) postcoordinated headings as more useful, both for end-users and for catalogers. More than one person mentioned the large amount of training required for catalogers to effectively apply headings from a precoordinated system.
I was struck in the discussion by the widespread lack of big-picture thinking about the issue, and the corresponding lack of awareness of the many initiatives going on in this area. There were certainly some members contributing to the discussion who have spent some time thinking about this issue, but many seemed afraid of the idea. I got the sense that many folks were trained on LCSH, that's what they use, and why in the world would they want to use anything else? When posts mentioned specific postcoordinated schemes (FAST, AAT, etc.) they tended to be mentioned as something the person had heard of but never used and didn't fully understand. I'm generalizing a bit here, but that tone was definitely present.
I don't know that I have anything concrete to say other than that I've noticed a trend of resistance to non-LCSH subject systems, but I do think that as catalogers are increasingly being asked to be metadata experts (and by that I mean metadata in a broad sense, not just traditional cataloging practice!) they'll more and more need to know about what vocabularies are out there. A huge part of my job as a Metadata Librarian is choosing among the various data structure and data content standards available for a given implementation. We're definitely past the days when one size (MARC/AACR/LCSH) fits all. The more all sorts of librarians learn about alternatives and can make good decisions about when they're appropriate to use, the better off our whole profession will be.