That example about having tons of advantages but darkness negating it, as a GM, If you're in a situation with so many (5+) advantages, you probably don't need to roll in the first place.
I think that's actually the opposite of the intent.
I think the rules intend that there's no such thing as a "perfect storm" of advantage, where you can just stack your way to success without rolling. And that idea works in conjunction with the "bounded accuracy" power curve as well. It doesn't matter how awesome you are, how well prepared, or anything--you can still be taken down.
It's like the movie Office Space. They have the perfect plan (advantage), with the idiot company not paying attention (advantage), with the right team to pull it off (advantage), but because the programmer misplaced a decimal (disadvantage), none of that matters.