Pipeline, excellent!

There are some minor things that if it was up to me I would do.
For example the way you select wavs / midi etc for dragging. Ctl+drag is an elegant way, but at least half (if not more) people are "mousers".

One way is to have additive clicking without the need to hold shift or Ctrl with reset on next generation or first "drag-to-daw" or similar rules.