I'd like to suggest that after a Question receives an Accepted Answer, some consideration be given to revising the title (if appropriate) to reflect what the real issue turned out to be.
It seems to me users often pick titles when first posting a question that are uninformative and are worth revisiting once the actually point is identified. Improved subject lines will help in searches, and by extension help with identifying duplicates.
High rep users, it seems to me, are not excessively shy about making changes to tags, which helps with later searches somewhat. But I think a good title trumps all that, and the SE search engine can use all the help we can give it.