I'm a minimal tag guy too. I can understand where Starson17 is coming from, there certainly are some "interesting" tags out there.
Now if every single book was consistently tagged with those "interesting" tags (be it a character name, a location, or whatever takes your fancy) then maybe I would be tempted into doing as dwanthny says of using a separate genre column and cutting loose.
However the OCD in me just detests the inconsistencies which would mean I could never use it to search. For instance say I wanted all books that were tagged "NZ" to indicate a NZ location. There could well be some books in my library which will have that tag. But I can guarantee that the majority will not. So I will be better off googling and then seeing if I have the books it finds. The same applies to any tag you don't set yourself, due to the lack of data scrubbing and control.
Let alone all the "Sci-fi, SciFi, SyFy, Science Fiction..." variations which do my head in.
But that's just me - you love 'em or hate 'em...