Most policies have multiple flavors associated with them. Pull up the big chart that has the flavors of each leader, and compare the higher flavors of each leader with the flavors of each policy. Adjust the flavors for the policies as needed. Keep in mind that there is an element of randomness in the AI's choice of policy (based on, essentially, a dice roll) flavors add weight to certain rolls of the dice, but they don't guarantee a civ will choose one over the other. You might also try adding new flavors to each policy (for example, if the AI likes religion, you could add flavors for religion to Tradition or Liberty by copying some of the existing XML and modifying the flavor type).
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