I disagree strongly. For the Empire to "need" a god of magic, first magic needs to be seen as a good thing. It just plain isn't. If tomorrow the Emperor rescinded the Articles of Magic, the citizens of the Empire would go back to burning every witch they could get their hands on, and thank the Emperor for his wisdom in restoring the natural order. And I am not sure if this will ever change, no matter how many heroic wizards the Empire produces. Necromancy and Tzeentch have just extremely thoroughly poisoned the well in regards to magic for the entire culture of the Empire.
Perhaps in half a millenia or so, with dilligent work, magic will become something commonplace and accepted enough that a benevolent god of magic might become a thing, but given miscasts are going to happen as well as human nature, i sorta doubt it.
Even Imperial Wizards don't need a god of magic - most colleges are taught in a firmly atheistic outlook on the world, seeing gods as merely aethyric entities that are not needed for magic to work. Those who aren't, mostly parts of the Jades and Amethysts, already have deities that fit their particular outlook on the winds.
Thats... thats the point, they need a god of magic because magic needs to be seen as a good thing. "Things are what they are" is not an answer to "things should become better".
And whether a god becomes important after a subject becomes important or a subject becomes important after a god does is a chicken and egg question in warhammer. Sigmar MADE feudalism and empire building important, so he became a god of it.
The times aren't changing enough for something like that though. That would take a truly cataclysmic event to happen and it hasn't. Something equivalent to how Sigmar created this entire new method of organization for the tribes that used to live in the area that became the Empire.
This is literally Myrmidia. She's all about pragmatic tactical and strategical combat as opposed to the more muscular strength of arms of other War Gods. If there was demand for this kind of thing she'd have more followers in the Empire already.
Problem is the Dawi already have a God of Radicalism, or to be more precise every god they have is a god of radicalism. Remember the conversation with Cython? All the Dwarven Ancestors were radicals in their time. Trying to create a new Radical God would only lead to whatever advances they introduced becoming normalized and Traditional because that is just how Dwarves work, on a psychological/sociological level.
The times are a changing faster than that, thanks to the effort of Dragomas, and they could change faster if we act well. Despite what fantasy authors would have you belief, a generation is a long time for a belief to change. Also, one could do it like Sigmar, changing stuff one feat at a time.
Its also not pragmatism in combat only, but in general such a god would espouse, not only in killing, but in bettering society or forming countermeasures. I doubt Myrmydia would create a dragon monolith.
As for the Dawi having a god of radicalism... I am all with you, man, I merely presented why such a concept should exist and be strong, not that Mathilde should embody it. The how is immaterial to what I am saying, is what I am saying.
This all sounds like the god of things SV questers like rather than filling any real need of the actual people on the ground. It's trying to make a god to change society more than it is truly adapting to changing times. the gap between pre-Imperial life and early Imperial life (after the dwarfs uplifted the tribes) is vastly greater than between pre-Colleges and post Colleges. While magic as a force may touch the lives of many it does not do so with any real visibility.
On the matter of dwarf radicalism it isn't all one thing driven by some desire to be awesome, it is a catch all term for any attempt to change society, many of those ideas are going to disagree with each other as much as they do with the conservatives. Trying to make a god for all of them, a god of change for the sake of change that is of a thousand minds... well there is a name for that and it starts with a T.
Well, yeah, it is a god of (some things) SV questers like because Mathilde is played and shaped by SV questers and she is played to be good and (mostly) moral in a way SV questers perceive such things. Its a shape shaped by itself, whether it is a good or bad thing is another matter entirely, however.
And while the gap of pre and post imperial life is greater for most people, you should ask any wizard what the gap of their life is pre and post colleges, and also consider if there would even BE an empire without Teclis and Magnus creating a source for human magical corps. A god of magic is culturally important, even if they do not wrestle primacy from Sigmar, and over time they may become more important still, as society evolves.
As for Dawi radicalism, it is a god they need because it is a concept they need, that change and progress is good sometimes, even within boundaries. A lot of gods make real estate by wrestling concepts from chaos gods, placing them within boundaries , and making them serve humanity rather than insanity, like, say, all the war gods vs Khorne, Ranald vs Tzeench, Mor vs Nurgle (on acceptance) etc.
Maybe the Empire does need a god of magic, in the same way Nehekhara had Asaph, but it doesn't follow that it'd be Mathilde who would get it. Let's be honest with ourselves; Teclis did an outright primordial-legend style thing when he gave proper magic to the Empire two centuries ago. As in, even random peasants getting sermons from their parish preachers in the far corners of civilization know that he did that, so that their priests can say with some accuracy that everybody who spurns the good and noble imperial institutions of magic use the breath of daemons to work their evil.
Teclis is already the ultimate watchword for authorities on magic. Even the evil wizards use the theories and practices he passed down, because they're so much more comprehensive than what they were working with before.
We'll never be more 'god of magic'y than the living Prometheus-Figure who saved the Empire by being better at all eight kinds of magic than their associated Patriarchs at the same time.
And I never actually stated it would need to be Mathilde, just that the domains are needed. I am all for making Teclis a god of magic for the Empire, why not. I disagreed on the premise that the domains were unneeded.