Mr. Henry Clarke has just released a new YouTube tutorial demonstrating how additional instruments can be added to the original Legacy Tracks:
Thanks for the video link Charlie, I watched it twice.
Mr. Clark pointed out several times that we're limited to just 7 instruments to work with but what I think I learned from him is that you can add more by clicking on RealTracks and (aliasing?) additional instruments but they will always be called "Strings"? I was a bit confused about that. He spent a lot of time talking about how to edit vocals.
In any event, he didn't show how to re-group/re-position the instruments in the Mixer Window which I don't think is possible at this point in the development of BiaB.
Jim's wishlist request above captures this wish very nicely.
FWIW, I think I mentioned drag and place or drag and drop as the way to implement this enhancement which was presumptive of me. I mentioned drag and place only because that is how you do this operation in Studio One and I find that approach natural. I'm sure there are many many considerations that the programmers must take into account to make such a change (if they choose to make it at all); considerations I am not privy to. If they do make this change I'm sure whatever mechanics/user steps they design will make sense.