A really bad argument for immutability

The immutability of God, as I have said before, is perhaps the most abused of God's attributes. The reason, I think, is that it seems to be the easiest divine attribute to grasp, so in our misplaced self-confidence we take liberties with it. And there is also the influence (though always denied) of Aristotle's Unmoved Mover.

In my opinion, the worst argument for immutability is this:

God cannot change from state A to state B, for either he was perfect in state A and then no longer is after changing to state B, or he was not perfect in state A to begin with. In either case God would at some point be in a state of imperfection, ergo not God at all.

Utter nonsense. Total crapola.

We can just as easily postulate a more sensible argument (that is still wrong) that God must change order to remain in a state of perfection. Setting aside what "pleased" and "angry" mean when applied to God, we must only assume they mean something. Now if God is, at the moment, pleased with me and then I sin, he would be in a state of imperfection (untrue to his own nature) if he did not, in light of my sin, change his disposition from pleased to angry.

The response to this argument is usually a weird hybrid fallacy involving an ad hoc argument and question-begging. Something like this:

But that is not possible, because that would make God reactive to the whims of man. 

That is both ad hoc (or "goalpost moving") due to its simply tacking on an unproven assertion (that God does not react to man's behavior) and question-begging because the tacked on assertion (that God does not react) is essentially the same as what is to be demonstrated (that God is immutable), creating a circular argument.

I have seen no valid philosophical argument (it's all word salad) for the immutability of God. The only legitimate argument is an argument from scripture. And there we must limit our understanding of immutability to what is revealed, and not extrapolate it to some place on the basis of philosophical arguments that hang on a shoogly peg.