Mastery is about instinct. Expression is about planning.
They do not seem to co-exist. In areas where they intersect, goals and motivations become muddled and confused. Mastery mechanics become meaningless through weak systems or save-and-reload style user control.
Games are typically designed to explore the former and not the latter.
It is likely no coincidence, though, that the top rated and top selling games skew heavily percentage-wise back to Expression, so that they are far more balanced again.
Mastery benefits greatly by extrinsic motivators such as story, pointification, and levels, that provide rewards and focus the mind on the suggested goals. Expression benefits greatly from more intrinsic motivators like rule-system control, accessible expert-knowledge, and creative creator-spaces.