In the past few decades, we have seen more and more of the latter.

In School A, when a writer is offered, say, Superman, s/he thinks "Can I tell interesting Superman stories?" In School B, given the same offer, the writer thinks "Can I use Superman to tell MY stories?"

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I will never understand the impulse that puts people in School B. If anything, it seems like the more difficult route (considering how amazing these characters are). A few years ago, for writing practice, I fooled around with some Marvel and DC characters, most notably the Fantastic Four, and found that when treated with their essences intact (in other words, following the examples of Lee and Kirby and JB, etc), they seemed to write themselves. Idea after idea pops into mind when those characters are just allowed to be who they've been for most of their history.