IF you are going that route, may I ask to “bundle” common pins next to each other? Like all the OLED, BlueTooth, the three typical Data (blade, PCB and Plade Present), etc? And please make battery charge a built in thing. Or at least easy to put an USB-C to do it all. I find that cable soldering and routing is the most time consuming part of a build. Having htem easily next to each other and needing a single port for charging, programming and loading soundfonts is what makes it really flexible.
I group the pins when I can, but placing the pads where it makes the most sense sometimes makes routing the board impossible, so I often end up re-organizing the pads to make routing easier. (Sometimes several times.)
USB-C ends up being bigger, more expensive and makes extending the wires a lot harder. The only advantage I’m aware of is that most people have the cables already.
USB charging is already a part of the V3 board, and will almost certainly be a part of any board I design in the future.
USB-C is also reversible.
The nice thing of USB-C (besides reversibility), is the total power and the possibility of separating the power signals to a different charging circuit, thus enabling a killswitch while charging. This is the old way to charge the batteries. But now that I think about it, I should have wished for actual deep sleep. The USB-C port should be easily solvable with an USB-C to USB 5 cable adapter.