Jon is here because of the fans, hopefully come next album and Tour his vocals may be a little better ( not exceptional, due to age and tear on his vocal cords that he's done to it)

I would be shocked if he retired after the tour! I am probably in the minority here! But I want Jon to continue after this Tour!

I think John Shanks gets what type of songs the fans like/dislike now being on tour, but again he works with Jon's current voice limitations that he has. Wouldn't be different if Jon hired another producer.

And it's unlikely Jon is going to have a voice op, unfortunately. He knows he needs to work harder with what's left, with his vocal coach to keep on continuing till he wants to quit for good.