The Space Launch System is a big red herring in terms of the direction space travel should be going. The age of Apollo, where people launched giant expensive super-rockets in order to prove their nations' technical superiority, and, indeed, the feasibility of manned space travel, is over. It would be folly to bring this back, when we are on the verge of the next step into space - a practical and sustainable network of transportation of humans around the solar system. It is not enough to just "visit" an asteroid, or a Lagrangian point, these places are useful for real reasons, more than just propaganda. While not definite, the Falcon Heavy certainly COULD enable the long-term usage of these resources, thru inexpensive and frequent launches, while the SLS seems geared toward just "getting footprints on something".