The Ran in his derashos (derasha 11) addresses this point directly. The Ran writes that the King's role is תיקון מדיני, we would translate this as civil law. The Ran writes about the Torah laws אין ענינם תיקון מדיני כלל. The purpose of Torah laws has no relation to תיקון מדיני (although it may accomplish that as well). Rather, the purpose of Torah laws is לחול השפע האלוקי, to bring down the heavenly influence.
The Ran's postion can be summed up by this quote:
ומפני זה אפשר שימצא בקצת משפטי ודיני האומות מה שהוא יותר קרוב לתקון מדיני ממה שימצא בקצת משפטי התורה ואין אנו תסרים בזה דבר כי כל מה שיחסר מהתיקון היה משלימו המלך
Because of this we might find that some of the gentiles laws are closer to perfection in civil law then what we find i sone of teh Torah's laws, however we are not missing anything because of that because what ever is missing from the Torah the King completes.
This Ran clearly conflicts with the current Charedi hashkafa about Torah. The Ran clearly and unequivocally states that Torah is not complete (the purpose of the King is to complete things) and that the laws of the gentiles may be better/more complete then the Torah laws.
