The biggest difference between a new game designer and an experienced game designer is understanding the difference between being able to create interesting systemic interactions with elegance and balance, and the role of the designer as someone who's job is to primarily create systems that can be adequately communicated to players who, fundamentally, have a limited input and output capacity physically, and will never perceive all elements of a design you put in front of them. Communicability is often the single most important element of any system or mechanic, including the decision to not communicate systems or mechanics. The systemic is endlessly interesting; the perceptual is endlessly important.