A couple of things about this:
First off: this is what happens when a song stops being contemporary and starts being myth. I mean, compare that parody to this one*:
The latter assumes that you’ve seen the original; the first merely assumes that you know of the original. Completely different humor.
The second point actually comes from my wife, who pointed out to me that the reason why the first video works is because the composer to The Hobbit was not creating medieval music; he was creating music that would sound medieval to his listeners. Actually trying to make Michael Jackson work to most authentic music of that time period** would be much more difficult. Syncing Jackson to this is a simpler process.
I know, neither of these observations are particularly earth-shattering, but they are largely what I was thinking about today.
Moe Lane (crosspost)
*A look at the original might be instructive, too.
**When my wife isn’t being an engineer, she’s being a Medieval Studies major, with emphases in music, performance, and the Anglo-Saxon period. She is pretty much as frightening in those as she is in engineering, which is to say: pretty dang frightening, indeed.