The whole Cataclysm needs to be redesigned. As it is, it just makes no sense.
So this god, who can come down and take mortal form, can't deal with his own priest. Despite having 25 Wisdom, (I'm assuming) he can't explain to his own priest that what's going on is wrong?
People say that the clerics were stripped of their powers, but they still had the mojo to enact whatever ritual had to be stopped? Where did this power come from? Why couldn't 40th level Cleric/40th level Solamnic Knight (or whatever) deal with an 18th level cleric limited to 2nd level spells?
And if Evil is so necessary to the survival of the world, why is it criminal to do those evil acts? Every murder is ensuring that Krynn won't be destroyed in a horrible flood of Good.