The bigger issue is that MIDI is reasonably good for keyboard instruments but it sucks at almost everything else. So as long as you look through the lens of a keyboardist you might think the only problems with MIDI are related to the fact that it isn't ideal for editing but the real problems go much deeper. If you feel the analog controller bits are the issue that's closer to the truth, but music is about as analog as it gets and any attempt at digitization will lose some expressiveness.