Naturally, from my perspective, when you sell a pedal, designed to be hooked with 4 cables in a Pre/Post configuration, the first thing that comes to mind is potential ground loops and signal level issues. I can't comprehend how something so simple can be a problem for you guys. Strymon does not have this problem at all with their Mobius. How come you do!?

Strymon does have this problem with their Mobius.  We talked about whether it was even a good idea to add pre / post given the fact that this was going to lead to ground loops for some people long before we started working on this feature, because we knew from the feedback of Mobius users that this was going to lead to ground loops.

We decided to do it anyway b/c (1) not everyone was going to have that problem (2) there are products on the market for addressing ground loops (3) you don't have to use it in the effects loop of an amp in the first place.  It's useful just moving your H9s position in your signal chain to before or after other pedals.

With regards to your guitar signal coming in weaker than your amps signal, a fair number of people have gain control on their amps effect loop.  If you don't, you can buy a boost pedal for your guitar on amazon for as little as $30.  If you have a weak signal coming in from your guitar, boosting the signal will also lead to things sounding better overall, because the H9 will have a better representation of your guitar's signal before it goes through A/D conversion.