I’m wondering if this isn’t a sign of the increasingly skeptical or critical nature of the audience since some of the worlds oldest stories never had this. Gods were Gods and they did God things. We had a vague understanding of ranks among the Gods, but no defined rules of what a God could or couldn’t do were ever defined. Most creation stories feature Gods creating things from obscene ingredients completely at odds with anything plausible as we would know it today. Even in later stories like the Lord of the Rings, Gandalf pretty much just does Gandalf things. Dumbledore or the Harry Potter universe never exactly had a system of magic- they just...did things. And these are still awesome stories. Further, it shows that such stories are not about “the power” necessarily, but the plot.
I think each one has it’s merits and might even give clues to the personality of the writer. Writers whose power systems are undefined are probably more open-minded, cavalier, fun-based, and the ‘do it for the pleasure’ sort. System-writers are probably technical, analytical, somewhat rigid, structural types. Their stories will not be the endearing, sweeping flights of pure fantasy and wonder, but contemplative, analytical interpretations or projections on things.
I’m definitely of the later sort, but, just like in real life, I sit in awe of people who can enjoy and bring joy to the lives of others just living for the moment and never really thinking too much on what they are doing. They have a gypsy-esque magnetism to themselves (I always wanted to meet a gypsy...).
At this point, I’d like nothing more than to sit by a large autumn fire a d hear a master tell their tale. I think I could live and die like that in peace...