My guess is that Cubasis is rather a test-the-water type of app. Don’t get me wrong, I am sure that it’s more than adequate for a person with good old compositional imagination, but I think that it is just the beginning.
As for Steinberg confirming or denying your questions above, they cannot reveal any information of future product releases, and as for your second questions, they will of course implement new features as they allocate time to do so, for a price that likely is yet to be determined.