Hi Mark,
Sounds very promising for most. I'm gotten smarter with the API and have moved to using a set of map packages displaying a variety of raster data as base maps on dynamic map service layers, and I have provided ordering and transparency capability for each. If this new feature is available for them as well, I think I can pull this off.
Thanks,
Carlos
P.S. Got a release date, yet? How about a teaser 🙂