I ran a successful Kickstarter with what I believe to be a cruddy video.
https://www.kickstarter.com/projects/1985705009/pimame
I think there are two spectrums to successful Kickstarter videos: Over the top really well done quality videos, and super low budget (read: $0) iMovie videos that show sincerity.
Anywhere in between that and you come off looking like a scam.