While its sad to condense a person's life into 6,5 minutes, a testimony indeed on how little attention span we have these days, I reckon it also calls for great skill to condense a person's life into 6,5 minutes. It's like the unwritten rule that a good radio hit should be no more then 3 minutes long. Yeah, you can say you don't want to conform, and complain about the listener's attention span, there is also great skill and ability to be able to trim down the fat until only the barest of bones of musical goodness remain. In my last band I started out writing long songs, and I will always enjoy writing long songs, but I also learned to enjoy the challenge of being able to trim down the fat into a 3 minute song.
So, while I would perfectly enjoy a full 2,5 hour documentary on the life of Clapton, I did appreciate this brief short one upon watching.