Proposed new "law" of evolution
Several things:
First, unless you want to redefine metaphysics in the current era from what it has meant historically, the role of "magic" cannot be excluded from it's repertoire.
To be clear I am NOT using the term "magical" perjoratively or dismissively. Rather I mean it as a explanation that defies observation, experience and knowledge.
If one is intellectually honest one cannot reasonably evaluate the role of metaphysics using it's current application, because in the current era we can only know the question, never the (true) answer. No, in order to fully evaluate what metaphysics is (and more importantly for this conversation, what it is not) we must use historical examples and put ourselves in the mindset of those in that era.
For example explaining lightning in the absence of an understanding of electricity. Judaism, Christianity, Islam and Hinduism all ascribed lightning to the workings of gods (surprising no one) when those religions were invented in the Bronze and Iron ages, clearly not science, that's metaphysics. However, in Medieval times lightning (which commonly struck the tallest structures ie churches) was either thought to be prevented by the piety of the ringing of church bells warding off evil spirits (a metaphysical proposal) or that the sound of the ringing of the bells disrupted the air and thus prevented the lightning from striking the tower (a physical or a scientific theory).