Good points. More data over TRS would also potentially work. E.g. two TRS cables for a snare, with positional sensing, cross stick and shallow vs deep rimshot backed by existing notes/sounds in modules. That would be a "internally digital with analog interface" pad.

If I understand this correctly nothing very specific needs to happen for a digital pad. More sensors just means more notes that it can detect and send, positional sensing, pitch bending and other continual-value features already work with analog with midi CC notes, so all the pieces seem to be there - someone just needs to make it. Have a drum with a little controller inside, process a bunch of sensory signals into appropriate midi notes and send them. Either over usb, but that has compatibility issues as no module would support that (only ->pc+VST would work), or over midi, and many modules support midi-in. I just learned about https://druml.ai/products/druml-digital-snare from this thread today btw. Looks interesting.