I can think a lot more complicated music than I can play. I don't always have access to a keyboard. Piano is a good instrument but sometimes I want to write drums. Also sometimes I want to express relationships between the single notes, not just have the notes themselves. To record 10000 notes from a piano, you need to hit 10000 keys possibly more than once to record them. My thing will let you achieve the same thing with less than 10000 actions.
I agree with you with respect to representation. Pattern/sequence generation is something most DAWs don't have outside of something like Cthulhu which the languages can do easily.
Another thing I've been dying for is an easier way of layering sounds, for example drum hits. Multiple midi sends feels hacky in Ableton and certainly not a first class feature. On the other side of things, the pain of rearranging multiple wavs after wanting to change a note is even more painful.
I totally agree with you about the actions though. Configuring plugins etc can be a huge drain and its very mouse heavy.
I'm not sure if I understood what you meant with layering drum hits. If you mean being able with a single trigger to have layered samples go off that form a drum hit like a snare or bass, then some drum samplers come to mind like Geist. That's the one I personally chose due to wealth of flexible features, but layering a group of samples into a single "hit" is a foundational feature in the program.
> Another thing I've been dying for is an easier way of layering sounds, for example drum hits. Multiple midi sends feels hacky in Ableton and certainly not a first class feature.
Layering drum sounds is a typical feature in all DAWs, and in ableton, with it's instrument and drum racks, it's even easier to layer whatever you want. May be I don't understand what exactly are you trying to achieve?
What is so arduous about plugging a midi keyboard in?