I guess we all work to our goal in different ways utilising the tools we have. I can see that more flexability and support for midi would be great too for many. I do think the sky is the limit in development though, I can think of many ways that I would proceed with additional content and features but I imagine PG have to aim for a wider more general market and also keep developement cost to a minimum. They have done a brilliant job so far.
I started out with 3.1 as well, magic for the time. These days I generally use bib to create and develop my own song backings and I find the quality and flexability of the realtracks are fantastic for that but I generally try and play my keyboard/synth rather than using midi and I record using Sonar/Guitar Tracks for my guitars and vocals. Which all works together for me and I have quite a good work flow process going now. Bib is such a great virsitile tool I for one would be lost without it now.
Jeff