My guess is that at some point Paradox will visit the time period currently covered in Victoria with their new engine, but to what degree the new engine game for the period from the mid-19th C to the eve of WWII might resemble Victoria currently is very difficult to say.
combine that with the fact that the old engine is now avialable for additional outsourcer development, and my hunch is that while you'll get some new expansions to Victoria as a result (with yours truly here in the beginning stages of such a project) I don't think Paradox will develop a Victoria II per se with the new engine, but rather a new title based on the time period with different mechanics.