What possible advantages or disadvantages of applying ideas from ancient civilization in your government?

Technically civilization is an ancient idea that we use today. As humans we tend to start with a base then build upward to perfect a concept, object, etc. Everything you apply to anything at any time has an infinite amount of possible outcomes(if you believe in that concept). == Any modern society branches from an older society and carries on already conceived ideas then changes them to the needs of the time period. We are using ancient ideas so we do not have to start from absolute scratch, building upon and reconstructing the details but never changing the roots. You cannot change the roots without removing the whole thing and starting with a new idea. Its exactly like building the Great Pyramids, as you ascend upward creating more layers it grows in complexity. Once finished it barely resembles what you started with. Im going to have to say there is no concrete and cannot be answered correctly with the current question.