First, regarding RAW:
I used to be excited about the possibility to shoot RAW. Then I started reading Ken Rockwell's site a lot, and he pretty much talked me out of messing with it. He talks about it in numerous articles on his site, but also dedicated a full page to it here:
http://www.kenrockwell.com/tech/raw.htm
A few quotes from his page:
"Some fancier cameras save this raw data so you can use software to do the same thing the camera's hardware did, later. Software takes much longer to do the same thing the camera's hardware does, but gives less confident people the chance to try to fix mistakes later."
"I almost never shoot anything in raw, and when I do I never see any difference for all the effort I wasted anyway. (I can see differences if I blow things up to 100% or bigger on my computer, but not in prints.)"
Regarding Lenses:
The option for virtually unlimited lenses through adapters is another big potential that you mention, and you make it sound like people who stick with the 2 original kit lenses are not utilizing the camera to its fullest. Unfortunately, a lot of people simply will not have the money to explore the countless lens options, so I would rather say that "they're using it as much as they can," rather than "not using it to its full potential."
I also believe that someone who really knows how to take great photos can produce much better images using either of the kit lenses than a deep-pocketed amateur who has $10,000 worth of Leica glass mounted to his NEX. I've seen images that Ken Rockwell has made using really cheap cameras, and I'm doing everything I can learn as much as possible in hopes of producing images as great as his with my NEX-5. I currently think adding a lot more lens options in my camera bag would do me more harm than good - it would certainly slow me down as I try to figure out the best lens for this or that situation. Instead of taking pictures, I'd be fuddling around with lens settings. The two kits lenses are enough for me for now.
Am I not using my NEX-5 to it's fullest potential? Maybe. But I'm using it as much as I can, as often as I can, and am trying to learn every piece of it's standard functionality, from HRD settings to Flash Compensation and on...