However if Harry were to turn the Castle into a place of contemplation and learning, doubtless Mouse could draw upon that instead of the threshold. ”Castle Dresden, home to the University of Chicago’s Vadderung School of Magic” Forget the Hulk, Mouse would be Galactus. But much nicer.
I suspect that -- in the Dresdenverse -- "family" makes more/better threshold than "a bunch of magic-geeks" do. But I haven't seen a WoJ speaking to that point, so it's pure speculation.
There are quite a few things about the current training regime Harry disagrees with, and the next time he comes across a young wizard I doubt he is going to pack them off to the White Council. If only he had access to wizard on the outs with the White Council (say by inconveniently coming back to life) who was for example a doctoral candidate and owed him his life.
Yeah; in another thread, the issue of young-talents-going-warlock, and the auto-execute policy, and why-not-catch-em-and-train-em-younger has come up.
I think the meta-reason is, it lets JB write the stories in the setting a certain way. But in-universe, it seems like it's really really hard to just FIND the little darlin' proto-wizards, before they go sithmode; and even a little o' sithmode seems to be highly corruptive & hard to return from. "If once you start down the dark path, forever will it dominate your destiny. Consume you it will, as it did Obi-Wan's apprentice."
But I don't think Jim
wants to write the novel
Harry Dresden and the Pigdimples Academy. And while Harry himself might have wishful thoughts in that direction, he's too aware of the efforts of the Black Council, the Outsiders, the Vampire Courts, and all the rest, for him to EVER be willing to be associated with a peaceful school of largely-helpless young proto-wizards; proximity to Dresden isn't safe for them.
Still... I could definitely see Harry putting in some time (and some of those diamonds!) if he knew of other people who could (more-safely) undertake such a project; maybe Elaine &c, as an outgrowth of the Paranet... (though (given some of the fan speculations swirling around Elaine), I'm not sure "Headmistress Elaine" would actually be a good thing!).