what I'd like to propose is not merely a "Hardware Wish" but rather a new control concept based on the (theoretical) possibilities offered by the CAN-Bus on the Duet3. I know there already is the toolboard using the CAN-Bus for decentralized control but I thought about how to drive this even further.
In fact it should (technically) be possible to implement each function of a 3D-Printer (heaters, fans, endstops, Stepper drivers, etc.) as a single, self-contained board connected to the main control board only by means of power and the can-bus signals. For example a smart stepper driver board (I think this was already mentioned in another post) possibly with higher power levels available, a smart mosfet board for the heated bed, different styles of toolboards with different hardware options e.g. you don't need a stepper driver at the hotend for a bowden setup, if you add a digital/analog input board you could even go for a "brain-only" main control board. Just to name a few ideas.
I think this would add an enormous amount of flexibility to the ecosystem as a whole, consider a Voron2 printer which ends up depending on the configuration with up to 9 stepper motors. Of course this is already doable with current products but a decentralized approach could be much more elegant.
Has something like this ever been considered? I´d be happy to help with elaborating this further and could even lend a hand developing the hard- and software necessary.