Nope, if we knew what the features were, we would bring in our own "biases" from our own experiences (be that financial or scientific). Without knowing what the features are, pure machine learning techniques are the only things that matter.
It also helps Numerai in that anyone can participate. If the features were known, a lot of non-financial people (like me) might not even be bothered to take part, because everyone trained in finance might have an edge over me. With unknown features, everyone starts on the same level.