Searching for actors in role classes is difficult

I'd like to be able, for instance, to search for all movies featuring John Travolta as a villain. It's that "villain" part that causes problems with most current search mechanisms. The most accurate way, but far from the most effective, is just to search Google for "John Travolta villain", though that will also show up reviews of John Travolta movies that mention the word "villain" in association with someone else. Perhaps "John Travolta as villain" would produce more helpful results, but only if someone has already gone to the trouble of compiling this information for me.

Mokalus of Borg

PS - It's not really this specific case that interests me, but the shortcoming of search techniques.
PPS - The problem is applicable in other domains, too.