It's looking good Suli.
There is one thing that I didn't notice in your list that I think would benefit many. Simply a means to have true
Track Based Midi. I use full song midi items for this now and it works okay, but it would be nice to have separate midi items across a track that were connected in a way as if they were full song midi items. Maybe this is too difficult to implement so that you can still use midi loops, I don't know. Even f it could be an option it would be great.
Another thing that bothers me in the midi editor. When I simply want to position the cursor, I often end up with a very tiny time selection. Obviously I must be unkowingly and unintentionally slightly moving the mouse a pixel or two. It would be nice if we had a little lea way for this.