Basically, there needs to be an "Aux In Link" checkbox on page 5 of the Master section (much like the "Direct Link" and "Monitor Link" which work so well for their respective signals) to decouple the monitoring of the Aux In from the Volume and Master Volume controls. As it stands, it is impossible to monitor other auxiliary audio inputs when the Kemper amp profile is turned down, which is essential in some routing configurations, e.g. where the KPA feeds audio to a DAW and its aux returns are being used as sends to studio monitors, ie:
Guitar -> KPA -> KPA Send/Direct Out -> Audio Interface/PC/DAW -> KPA Return/Aux In -> Monitors
There are times given this routing where you need to monitor only the Aux In, while feeding guitar signal to the KPA Direct Out (e.g. to drive a VST with dry guitar). But if you turn down the Volume or Master Volume, the send is defeated. This is where the ability to uncheck an "Aux In Link" - to keep absolute Aux Level up and turn Volume down - would be very useful.
I hope this makes sense and I'd be happy to answer questions otherwise. I'd love to see this option in the next firmware. As it stands I have to change my routing to Guitar->KPA->PC/DAW->Monitors, which is less flexible and compromises the tone of the KPA considerably.