Overall I'm not saddened by this because he had an amazing career as Mario (and still perhaps as the many other characters he's done). There was always going to be this day and I am glad they're not trying to AI him into forever.
I just hope, like you, that this went down in a very good manner. I want him to be happy with the forward changes and I want Nintendo to be fully respecting him on every level, salary or otherwise.
I'm excited to see what the world holds for future voice artists. Maybe we'll get to know the new person/team soon enough. I hope they have a great personality like Charles does.