If that's what you're looking for, I highly recommend the "trained" end with Mahir, the one involving the charm. Consequences of that will carry over to the third game. In a more broad sense, eh, it depends. Obviously corruption does effect gameplay, in a number of ways. Certain areas, like the Center Path and Host Club aren't even options until you've "loosened" him up a bit, and the alleys have an entirely different mechanic once you're corrupted enough.
As for Raspy Voice, will have to wait and see :D.