Sorry fellas, I'm out of the office this week for training (see posting time). I'll try to get a full response up here sometime before the end of the week, no time right now.
We're on an annual release cycle, no plans for point releases anytime in the future. This allows us to deliver more year-over-year albiet more spaced out. You might not think that would be the case, but I can assure you it is. As for a Service Pack, we don't do those in Revit, we have Date Builds. Like Service Packs these are purely bug fix releases, and cannot contain new functionality. Our Date Build is coming soon.
Cheers,
Kyle B
Kyle Bernhardt
Director
Building Design Strategy
Autodesk, Inc.