I’m going to go with the answer that we want to move forward, not backward. We have learned several lessons since then, and these should be incorporated into our rockets and spacecraft. Problems that existed with the Saturn, the Shuttle, and with Apollo should be corrected. They worked, but the had their problems.

Saturn was a quickly developed rocket that was designed before we knew much about the pitfalls that come with sticking incredibly powerful, high temperature, high pressure, lightweight engines (each of which burned more than a ton of fuel and oxidizer per second, the equivalent of the output of 36 one-gigawatt power plants — per engine!), and finicky turbopumps on lightweight structures right next to the fuel tank. (You have my permission to be impressed.)

Typically, we want to design hardware that is appropriate for the mission at hand. For Apollo and the Saturn V, that mission was going to the moon and returning safely. For the Space Shuttle, that mission was to explore man and material in micro-gravity in low Earth orbit (LEO).

For SLS, we still don’t know, so SLS may not be the best design for us. The general idea is for SLS to take Orion beyond LEO, possibly to a high orbit around the moon (at one time a return to the moon’s surface was the mission), or possibly to a “local” asteroid. If only we knew.

Even if the mission were to go back to the moon, we would want to do more than just walk around for a while, we would want to move forward, such as build some serious infrastructure, like a permanent base or even a colony, and that could require more than a Saturn can lift (or an SLS, for that matter).

I would argue that a better design than the SLS would cost less so that we could launch it at least once a year, and preferably several times each year. More missions means more exploration, which is NASA’s purpose, and why we had intended for the Space Shuttle to fly a dozen or two flights each year.

I understand your frustration about the direction that NASA has been directed to take, but going back to old 1960s technology is not the best solution.

My recommendation is for you to become a rocket scientist and help take us into the space age.

http://space.stackexchange.com/questions/6281/why-not-build-saturn-vs-again