I really believe that if an actual scientific study[1] was done on this, it would rank right next to a pure fast food diet. It's not that it isn't theoretically possible to make something that is "perfect" nutrition, it's that we don't know enough today to say definitively whether carbs or fat causes metabolic syndrome[2], much less how all the various micronutrients interact with macronutrients, gut biota, and phases of the moon.
Until we understand every piece of the nutrition puzzle, this is just dangerous. That he wants to take it out to others is even more frightening.
Until we get to where we really understand what the body needs at an individual level, I'm sticking with whole foods. I really hope this guy doesn't do long-term damage to himself, or anyone else, for that matter.
1. Unfortunately, it is pretty hard to double-blind whether you get a Big Mac or a cup of gray stuff. This isn't just a problem with Soykent, it is a problem with every attempt to perform nutritional experiments. It is really hard to perform good, predictive science in this space.
2. We need to know like chemists know how chemicals will react and physicists know how forces will behave. We don't.