Potions is not the only thing that's neglected in canon; Transfiguration is also "just" taught but never used (except by the teachers). I love it that Harry!MoR puts Transfiguration to good use; after all it seems to be the most general magic manipulation.

It feels a bit as if canon and MoR aren't the same fiction subgenre. Canon is about a boy growing up, about action and an isolated society that still parallels the muggle society in many ways. MoR is more about discovering the magical world and about complicated plotting.