I don't think the internal workings have changed too much since it was adapted from the very old powertracks way back in 2000's. There would be so many different functions in it that work on uncompressed wav files as it uses destructive editing on the wav files, and not to mention all the audio FX functions that use destructive editing. If they get the BiabVST working like the Biab injector then you could do all the same things and more than realband can do in your favorite DAW. Non destructive volume automation was added to realband some time back after a user request and now recently added to Biab but other than that all else is converting to an uncompressed wav file then destructive editing it, so again it too would need all the wav editing/FX functions changed to work with other formats crazy
The idea of realband was great but it works in a slow way using a Biab application in the background like how the current BiabVST works, users stuck with Biab because of the speed but using the Biab injector method would be a lot quicker than Biab it's self not to mention being able to have a live arranger Biab also. I think most of the development energy goes into the Biab application other than a few tweaks now and then to realband. If realband worked like reaper it would be a way different story but that would be a massive undertaking, the horse has bolted frown realband was made after reaper was released that used non destructive editing.