As an avid runner barefoot running feels great and is tons of fun. I often do an hour or so out and back along the ocean. It definitely helps to improve running form and biomechanics, but I simply can't run as fast barefoot as I can in trainers or racers. As an HS coach I advocate 1-2 days per week of it.
Lighter is not always better. For competitive runners who are used to running barefoot, barefoot is faster than with shoes. For 200 pounders and runners who are used to jogging on their heels it probably doesn't make any difference.
A top runner is not always better served by lighter shoes. The design of the shoe is also extremely important. There area many ridiculous 5oz shoe designs. For one thing, the great majority of racing shoes have built up soft midsoles, which is totally ridiculous.
I think you should wear the heaviest shoes you can find.
Americans are usually much heavier than Kenyans, and slower. Wearing lighter shoes is not going to make as much difference to heavier runners, as I pointed out previously. Why are American marathon runners so much slower now than they were in the 1970's when everyone was wearing minimalist shoes? Huh there's a question for you.
BTW, you don't have to tell me all of your "scientific" viewpoints on barefoot running because I've heard them, but they are all theories. I'd like to see you come up with a better analogy. How do stabilizing muscles become lazy? Whether you are barefoot or run in shoes, you weigh the same, and that means your foot and leg still has to support that weight. Also, your "stabilizing" muscles are in your lower leg, not in your foot. There are very few muscles in the foot that do not extend up the lower leg where the origin point is.
I am so sick of hearing about this stupid barefoot running thing. I'm not telling barefoot runners that they can't run barefoot, just don't tell me to run barefoot and tell me that I will never be injured again if I run barefoot. Statistics show that if you are physically active no matter what you are doing, you will sustain an injury at some point in time. That is all I have to contribute to this conversation.
There are people now who run barefoot and run pretty fast. Not many but there will be more if for no other reason than that it's a good way to make a name for yourself. Running a 2:30 marathon in shoes is good, but not considered amazing by world class standards. Running 2:30 barefoot would make you a star. As far as I know the barefoot world record is 2:15:xx set by Abebe Bikila in 1963, so this is potentially another world record to beat.
There are actually many examples of fast barefoot runners. It's just that we don't usually see them running barefoot on television. Most elite athletes do some barefoot running as a part of their training. But, partly due to social pressure, and expectations, and more importantly corporate sponsorships, they almost all wear running shoes when racing (which is where we generally see them running).