The statement that FiveFingers are heavy (11-13 oz.) is simply wrong because there are numerous pairs under 10 oz. I myself own the Seeya's and those are ~4.5 oz.
Additionally, the fact that so many people on this website claim to know "basic exercise physiology principles" (a favorite phrase of those ostentatiously overeducated website trolls with their website PhDs) and claim that extra cushioning aids in shock absorption is interesting; they must be disregarding the multitude of studies and gathering evidence that claim that leg stiffness alters (and thus shock absorption) with the amount of cushioning placed under the foot. The less cushioning, the stiffer the leg, with the converse being true for more cushioning. In this way the body makes sure it allows the same amount of force to be transmitted throughout the musculature and skeletal system. I'm not going to be like the average Letsrunner and falsely claim to possess incredible amounts of knowledge regarding the exercise sciences, but with this in mind, how can anyone argue that one shoe is better than the other? The only reason (backed by evidence that anyone who knows how to utilize Google Scholar an find) that FiveFingers may appear to be bad for you is because of the fact that the majority of runners are older rather than younger and have thus had time to allow certain stabilizing and shock absorbing muscles of the foot, ankle, and lower leg to atrophy. Thus, when transitioning (usually too quickly) to a minimalist shoe such as FiveFingers, the body hasn't adapted as quickly as he or she would have hoped and the resultant is injury.
Elites are a no different. Take Alberto Salazar, arguably (or unarguably, depending on my mood) the best coach last year and so far this year. He has been quoted say that they (meaning the Oregon Project) will generally not change something in Rupp or Ritz's (just two runners I'm using as an example) training just for the sake of change; rather, they will only change something if it has proven benefits. While Fivefingers don't have any proven injury-causing features (just the idiots who transition to them too quickly), they simultaneously do not have any proven benefits either. Add to this the time it takes to transition from running years (in the case of Rupp and Ritz) at ~90-120 mi/week (+ any additional training done on the Antrigrav treadmills) and the transition time, without injury, would take months, perhaps even a year or two. Why would Rupp (who has a history of never having a major injury) and Ritz (who is healthier and performing better than ever before) risk this? I believe these reasons (remember, I'm just using Ritz and Rupp as an example, so this could apply to any prospering elite runner) are why you do not see elites transition to FiveFingers.
Finally, I will add that I love my pair and run in them quite often (I also use Saucony Hattori LC's; the best pair of running shoes, in my opinion), but I do think they're quite goofy looking. But, I also believe that, although unproven, when the transition to ultra-minimalist shoes such as the FiveFingers has been made, they do have an injury-protection factor to them, however small that may be. As with anything in running, you can't say FiveFingers are always "good" or always "bad," because that simply isn't true. Hell, there are plenty of people who break the "10% rule" religiously and are never injured, while people may need weeks to up their mileage 10%. Nothing in running (other than like chopping your goddamn legs off or something) can be proven to be always good or always bad, there are always outliers folks, and that applies to this argument as well.
Oh actually one last personal testament favoring FiveFingers: I transitioned to them rather quickly (yes, call me an idiot, I really do not care) but have luckily been able to continue building my milage without injury. Since I've incorporated them into my training rather frequently, I haven't had an injury in almost a year (my longest time ever) while also being able to very slowly build my mileage and drop 3 minutes from my 5k PR. While this injury-free, prosperous streak certainly isn't solely attributable to just the FiveFingers (I have also included more lower leg stability and strengthening training, as well as religiously doing core work), they certainly haven't hurt.