In some cases, a single headword entry can relate to a large number of topics. I have tried dealing with longer tag lists: automatic adjustment of tags column (on this list a little utility was posted: org-adjust-tags-column-reset-tags. I THINK that a keyword list may allow more freedom to cross-index, especially if it is easy to use.
Can someone suggest a way to implement a keywording system, perhaps with a custom agenda search? Or have others dealt with this issue in innovative ways?