Perhaps a bit out of topic but why not add scopes to the channels. This is one of the few things that I really miss from ProTracker. It was actually quite usefull.
Also it can perhaps be a idea to add a stereo-scope for to show both left and right channels summarized if possible.
What I have suggested before is to add a "faded" view of a waveform behind the notes in the editor

... that would be hypercool because you can see the final rendering of the sound. Also it can be usefull.
Ok I realize that I was terrible off topic here...

Perhaps we should make a summary of these requests since they are all related somehow I think.