I no longer use the pack you see in the above picture, but I still use the same set up. I now use an ULA Catalyst (lightening my load!). I still have the carabineer secured to the collar strap where my camera strap goes.
To take off my pack I must first disconnect my sternum strap, next remove the camera strap from the carabineer, disconnect my hip belt and then take off the backpack. If I don’t disconnect the camera strap from the carabineer I will have a camera hitting me in my neck. I know this because I have forgotten some times! When I disconnect the camera strap from the carabineer it is completely separate from the backpack and rests around my neck. It’s not a perfect system but it works very well for me.
The camera bounces very little because the sternum strap is holding it against my chest. If I bend over the camera would hang with the sternum strap being the pivot point. The angle of the camera strap behind me also helps keep the tension towards my body.
I have not had any problems with sweat on the camera. That could be because of the shirt I wear, my low perspiration, or a combination of both.
My camera is not a high end DSLR so I do not mind exposing it to the elements. If I had a very expensive camera I might not carry it this way because I would be afraid of trail dust and possibly getting hit by bushes, twigs, branches, rocks, or falling into water from a misguided river crossing!