How about an Automatic Material Unit. It would hold and load one spool. It could be large enough to accommodate more spool sizes than the AMS. It could even have an active drying feature. Maybe an AMU XL for multi-kilo rolls. This way I wouldn’t have to fuss with swapping between the AMS and the external spool every time I want to use filament that doesn’t fit in the AMS.
That would be amazing, I would only expect it to come along side a more commercial/industrial printer unfortunately. Though, this doesn’t stop someone from making an aftermarket unit using the core components from the AMS. I have thought about doing something like this myself.