With a second thought
, I guess it's even more complicated.
A player should get less points, when he wins with a strong civ, and more when he wins with a weak civ.
So we would need to compare
Strength(Player1) * Strength(Civ1) vs. Strength(Player2) * Strength(Civ2)
which would give us a set of linear equations.
We also would have to account for the fact, that some Civs are stronger on certain maps and weaker on others, and therefore we'd have to introduce a map-correction-factor into strength(CivX).
(Not to be taken seriously. Just kidding.
)