It seems to me that the original issue still stands. Firstly, I agree with everyone that recommend creating patches rather than using the presets. I invariably end up creating patches with just an amp model and very little else. The less things in the chain mean less time endlessly tweaking.
Regarding the presets though. I agree that they are provided with the POD to showcase the tonal possibilities. As far as I am concerned if I was trying to demo a POD in a shop environment (or when it is first unboxed at home to show a friend how cool it was) I would expect that I could connect a guitar to it then plug it into a physical amp (or PA / Headphone) and with the amp and guitar volume remaining constant switch through the presets without alternating between insanely loud and quiet as a mouse.
One of the first things I did when I got my POD HD500 was to go through each preset and adjust the output volume to be consistent. I could then switch between any patch without the fear of deafening myself. If I then change guitar all presets change equally relative to the guitar. If I turn up master volume on the physical amp then all presets change equally relative also. If I substitute the physical amp for studio monitors I only need to adjust the single volume on the monitors as all the presets volumes are still matched relative to each other.
As each patch has the ability to control the overall volume without affecting the tone there is no excuse for Line 6 not shipping the POD's with each preset volume normalised.
Like I say though. I do create my own patches but on the odd occasion I just want to goof around with the inbuilt presets. They need to be useable right out of the box. This means they need to be at the same volume.