The idea of being in total control of such a powerful alternate universe such as the Grid is just so awe-inspiring and imaginative. You can literally create anything. For Kevin Flynn, it was to recreate the system he had once visited in hopes to learn more about what he had experienced and take advantage of the life he could lead. In that way, he embodies all of us who desire for that escape and that ability to sink away into a world that you have total control over. His faults ultimately lied with his attempt to create perfection, something he could not attain in our world. That resonates with me. I have always held on to the idea that nothing is constant, that change is the opposite to perfection. Flynn never expected the Grid to change so he asked CLU to maintain the perfect system. He was so convinced that the world he had created would differ from the world above, that he could have some sort of constant in his life. The events that would follow proved otherwise.