I'm not sure how I feel about those opting out. There are legitimate safety reasons, of course, but there is also just selfish or probably more accurately, 'some things are more important to me than football' reasons (.ie money). It's difficult to know what's in one's heart, but it's also foolish to pretend it doesn't matter. Arguably, drive is as, if not more, important than talent. If I'm choosing between a guy with absolutely no question marks and a guy who may or may not have question marks, then, if the talent is close at all, the guy with absolutely no question marks is an easy, easy choice. Clearly, the scouts and background investigators will earn their money this season.
Reality is that I personally don't have football at the top of my list. I'm more about work/life balance. I think that leads to a healthier, happier life in the long-term. But my employer, particularly if it's in a profession with a shorter duration, would prefer me to be a fanatical, committed workaholic. And those guys who end up being special like a Michael Jordan or a Jerry Rice or a Tom Brady, etc, don't tend to be poster boys for a healthy work/life balance. They tend to be fanatics. They have chips on their shoulders over imagined slights. They run hills so so fearsome that other workaholic athletes think they're insane. They take their shoulder pads with them on vacation so they can get workouts in on the beach. A big part of what makes the NFL draft a crap shoot is that you can't measure heart. The NFL just measures things like size and speed. If that's primarily what you're looking at then you'll always end up right/wrong about 50/50 of the time. IMO if you get a hint that guy may be one of those fanatics, who'll do whatever it takes to succeed or a hint that he isn't one of those guys that will do whatever it takes to succeed, you have to factor that in. It will make your odds of hitting in the draft much, much better.