Vaio, that's very interesting! Thanks for commenting.
Being born in 1981, I was unfortunately too young to really have an appreciation for the kickboxing scene in the 80s (and obviously the 70s) but I do have vague childhood memories of seeing matches occasionally on ESPN or learning about pro kickboxers who had crossed over into movies.
Lately I've really gained a big interest in what was going on in the karate/kickboxing world at the time and have been watching and reading a lot of stuff. I actually think the subject of how full-contact karate came out of the traditional martial arts world of the era and eventually became "kickboxing" is a fascinating one and would make a great documentary.
Like you say, the full contact ruleset gets bashed heavily and the logic makes no sense. Its detractors say, "You can't elbow! You can't leg kick! This is so stupid!" But yet they praise and embrace boxing. In boxing--the most restrictive of all striking rulesets--you can do even less than you're allowed to do in FC kickboxing but somehow boxing is glorious and FC kickboxing, for being restrictive, is lame. Using this logic, MMA is the end all be all of combat sports and everything else sucks because it's not MMA.
Personally, I think it's a great form of striking-based competition and if I competed in kickboxing I'd probably want to do it under the FC rules. I love beautiful kicks, like Tremble's, and I think the FC rules foster an environment where you will see more high kicks, spinning kicks and aerial kicks.
At the end of the day, it's all just competition. For self-defense, you want every tool at your disposal. But for competition, the restrictions--what you're NOT able to do--plays an equal role in making things interesting with what you ARE able to do.
I'd love to see a revival of the FC rules, honestly. Or at least something else like the World Combat League.