I've always been suspicious of the Camelbaks on issues like keeping the water clean, and because it's so easy just to add a few small lightweight bottles of whatever quantity of water you need. After reading these commentaries, I went looking online for reviews, and while a lot of people are very pleased with the qualities of different designs, I found one review site where the reviewer dropped 50-pound bags of sand on various Camelbak-type water carriers, and many of them failed. In other words, don't fall on your back when you're out in the rocks, or drop your pack any distance, or you could be without water.
I have fourteen or fifteen different camera bags, collected over many years and never thrown out, and have given up on finding the perfect pack. For the Nikon gear, I now have one big roller bag that stays in the car, and a small well-padded Kata pack in which I usually put the D800e and a couple of lenses, and that's it -- in other words, I decide ahead of time what I'm mostly likely to need, and take only that, instead of taking everything. If I miss a shot because I don't have a needed lens, well, there'll be more shots. Or maybe there won't be. The world will remain unshaken in either case, and I will be carrying much lighter loads.
When traveling by air, I now leave the Nikons at home and take Panasonic m4/3 system. I can get two bodies and all the lenses I'm likely to need (including a 200-600 equiv) in a small auxiliary bag, with my laptop and other carry-on gear in a second small backpack. If my ultimate quality isn't as good as it would have been with the Nikon gear, well, once again, the world will remain unshaken, as will I.