No disrespect intended, but this is an example of "fan perspective", something many of us are guilty of (myself included) from time to time. We each have our own particular fascinations with some aspects, characters, devices, or whatever, from the Star Wars universe, and we sometimes tend to exhibit obsessive behavior by studying the minutia of these things endlessly. And because we're fascinated by these things, we project this mindset onto George Lucas and expect him to know them as well as we do. The problem is that some fans expect Lucas to know everything about everything within the Star Wars universe, a task that is virtually impossible even for the most hardcore Star Wars fan. And Lucas isn't necessarily a fan--to him items such as lightsaber hilts are merely objects that help to tell the story in some way, and he really couldn't care less about what they're made from or how they work as long as they serve their intended purpose within the story he wants to tell.
Now, J.J. is probably more likely to pay attention to the little details than Lucas because a) he is a self-proclaimed Star Wars fan, and b) he hasn't been directly involved with anything and everything that has to do with Star Wars for more than four decades like Lucas has. To J.J. Episode VII will be new and exciting; to Lucas it would be just another day at the office.