I'm interested to give XtraSavageAI a try. If nothing else it would be a change from the AI's current play style. Could you give a bit more detail on what exactly you've changed though?
a: The AI should build some more powerful individual units, going for quality not quantity, yes?
b: Expansion: you put a higher priority on late game expansion? What does that mean, build more Pioneers? In general what should XtraSavageAI do more of than vanilla AI before turn 50? Before turn 100? Before turn 150?
c: What did you try to achieve with your Domestic Policy changes?
d: What did you try to achieve with your Military Policy changes?
e: With City building, which buildings did you increase the priority of and which did you decrease the priority of?
I don't want you to cut and paste all the xml, but it would be nice to have a line for each section saying where you thought the AI could be improved and how you tried to achieve this.