If the Dresden books were about Merlin, it does seem to fit. Harry Dresden isn't Merlin yet, but he's getting there.
With magic like what we saw in the creation of Demonreach? I love Harry, but nothing human made that spell, imho. Or at least nothing human designed it; it's too difficult for us to think in more than three dimensions at once. Four dimensions is doable, we guess at that when we try to picture black holes, but setting up spells to run across multiple dimensions beyond our three physical ones + time? Egh. Not when Demonreach had to dumb it down in order for
Bob to understand it. Theoretical physicists imagine plenty of other dimensions, but they don't try to describe what it would be like to actually move around and
do stuff in them, other than maybe a fourth physical dimension.
Maybe something happens to Harry in the future to turn him into a super-genius(less Wile E. Coyote, more Stephen Hawking on mental steroids) which allows him to make spells like that-- but barring that, I can't believe it.