Videos do have one very important advantage: They can be played over. Certain concepts become easier to assimilate with repetition. One of my favorite instructors (I believe he was a psych major) used films ingeniously, and repeated them until he heard us bitching about "Oh, this again!" That was his indication that we had learned the material presented, he said.
Having said that, and coming from a video production background, I think you have a great grasp of the key issue: Just like some things are better coming from a book than a lecture, some things are suitable in AV form and others not so much. The trick is to learn which is which and not try to pound the square peg into the round hole, so to speak.
Schematic reading, circuit analysis, and a lot of theory can be enhanced by AV, especially with the judicious use of computer-generated graphics and animation. Tasks that are based primarily on visual or aural feedback are good. For instance, a soldering course would be quick and painless, I think, providing you had the camera and the videographer capable of showing you what you need to see. Other things need to be experienced in a hands-on environment to get them right. AV still only covers the two senses.
The advent of computer-based interactive AV makes certain things possible, but again, only when used well. I remember well, in the early days of interactive, an insurance company producer who spent days and days and who knows how many dollars producing an interactive training piece on how to use the various adjustments available on the standard-issue office chair! A big hit it was not.
A few things to always keep in mind:
Production standards are set by our exposure to the industry stuff we see every day; a guy with a camcorder, no matter how talented, can rarely meet those standards. Not meeting those standards means that your viewer, at least on a sub-conscious level, is paying attention more to the medium than the message. That is seldom the best environment for teaching/learning/conveying information.
Making good film/video is a LOT more involved than watching it. Assembling one of your kits, for instance, may take an evening. Doing it for an instructional video might take a week if everything goes very well.
A guy standing in front of a camera lecturing for an hour is almost always "tuned out" about five minutes in. So is a pretty girl, though perhaps for different reasons!
