But the question is how does this fit into Jafar wanting to change the laws of magic? Does he want to change the past so that his father never shunned him?
Probably. Obviously Jafar wants power and feels slighted by his father for abandoning him. He wants power (magical) and power to rule and he wants to be accepted by his father. And he has daddy issues on top of that. (Sounds a lot like Loki at that moment).