A downside to the introduction of the monthly updates was that Scott's "Power" books were no longer practical to produce. That was a big loss. His clear descriptions and instructions were outstanding and invaluable. I still consult them for anything that hasn't changed since X3.
Now that the updates has ceased, I would love to see him produce one last Sonar reference. Perhaps just some kind of supplement that covers features added since X3.
I realize that it might not be worth all the work that would be required, since a lot of Sonar users will moving to other DAWs. Nevertheless, I just wanted to put the idea out there.