Actually the Gackt fanvids are often OK, but I watch lots of martial arts or manga ones and they can let down (um - don't throw a good light on) the things that they are praising - which is a shame. And you're right: a negative example still teaches a good lesson.

The Moon Child fanvid which you found was beautifully done - the thinking behind it really scores! - so I hope that it does give you the encouragement to make more yourself. I look forward to seeing in the future!