In theory any energy change can be reveresed if you can put enough energy in to bring about that chnge, I think. To return Rathar and Mythar this would be something like: destroying all order and worshipping nothing at all, or returning the Valheru to Midkemia with them worshiping the Blind Gods. These were lost or 'died' because people started to worship more specific energy forms, e.g. Good, evil, fire, theivery and acted in such ways, thus forming more indivdual deities. As I see it anyways, where's that Gambler when you need him...
I can't see Nakor being Ishap though, he mentions impulsiveness in his youth brought on by being touched by a God, not something I'd relate to Ishap.
Anyone else ever wonder how much of the whole Gambling thing is just a front?