Thanks for the guru tag- undeserved, I'm sure.
The hip pockets are really only a stuff sack modified with a couple of straps. I use them when I have to camel up (4kg of water), and I do notice a difference when I move 2kg of water from my back to my hips. Otherwise they perform their duty as storage sacks in the pack.
It isn't something I do all the time, and it isn't a defect of the pack pockets or anything like this, it's just a way to balance better and walk more upright.
It might not work for anyone else this way.
I tried an Aarn bodypack, and while intruiged by the great design etc, with a base weight (big 3) of only 1 kilo, the weight of the pack and complexity of the design and my packweight didn't justify the style of pack Aarn make. The Mountain Magic 33 is one on my radar, but weighs 700g (+/-) and my Murmur weighs a third. I can effectively carry the extra in water weight.
The water bags don't bounce around, as I clip them to the shoulder strap, or sternum strap for non weight support.
I hope this helps,