Perfect brains would never make mistakes, would always make the right moral choice. God created us with less than perfect brains, brains that could make the wrong moral choice. That had to be god's plan, to make us that way, since he made us that way. If he had a different plan, he would have made us differently.
Since he intentionally made humans that way, he knew that we would make the wrong moral choice at some point. That also had to be his plan. Then, after making the wrong moral choice (whether due to the serpent or not, does not matter here because it is still the human who did wrong) he punished humans severely, every generation. That was also in his plan.
We were created with brains that could make mistakes. And were punished for making mistakes, using brains that were designed to make mistakes. God planned it that way.
That is like breaking your dog's leg, and then giving it to the pound because his limping annoys you. It is like trashing your own home in a drunken rage, and then having an arsonist burn the house down because it is such a pit. It is like a father throwing his daughter out of the house for being a prostitute-- when he is her pimp.
What is the A and E story not like? The actions of loving parents who care unconditionally for their children.
Any analogy you think up for this godly scenario is so repellent as to boggle the mind. How is that fair, just, kind or loving? How does the power and authority not rest entirely with god in this scenario? Didn't he know what he was doing when he created humans the way he did, innocent, immature, curious and gullible? A and E are like overgrown babies, right up until they do what babies normally do--color outside the lines-- and then get punished as if they were fully responsible, mature adults.
The only way this story even makes sense as a fictional myth is if the bible god is the same as the other ancient deities-- powerful, but not omnipotent; caring, but not completely benevolent; knowledgeable, but not omniscient. In other words, god in the bible stories is just like Krishna, Zeus or Shango: sometimes angry and vengeful, sometimes nice and generous, sometimes unwise and incautious, or capricious, or jealous, or guiltily distracted by a pretty goddess or human female. Fate affects the gods as well as the humans, and makes everyone's plans backfire or turn out differently.
Then the A and E story is just another cautionary tale of what happens when people or gods try to do right--they can still screw up: see Icarus, King Midas, Pandora or Loki. The lesson is not "always obey god no matter what and everything will turn out well" like Christians might want to think. The lesson is "do the best you can, things just are the way they are and sometimes not even gods can outsmart or outflank fate."
Hardly a story about the ultimate creator of the universe, just a story about a larger than life version of a normal human king. How he became all that and a bag of chips is the result of the endless "my god is bigger than your god" contest between the ancient peoples. The rest is dramatic irony.