Aye Major, I do think there is room for stuff like that. Either go with adult wizard, a bit more Pratchettesque absurdity, get more creative with the setting as well. Or you stick with the teens but make it more of an adventure game rather than straight-up wargame. I'd look at the solo/co-op rules for pulp alley there as well since it allows characters to have multiple areas of expertise outside of straight-up fighting which are used to resolve objectives and obstacles during the game.
Looking at that document again I am full of mixed feelings. 10 years have given me some more nuance in there and there are ideas that I feel could be interesting to explore but would do well with a better writer than me. Replacing house-elves with Imps, who have a liberation army intend on abolishing imp "slavery" is a powerful motive, but I always imagined using goblins like the kings of war vanguard goblin wiz but painted red.

Which gets into that territory where a good writer could make something comedic yet poignant and soulful but slavery is a touchy subject I honestly don't feel comfortable putting in my fantastical "funny" game? Going "its ok they are summoned and bound demons not real slaves" definitely wouldn't be the way to go.
But then I look at the 4 main factions I created, which are the main power blocks that remain after the big dark overlord was sort of defeated but shattered the wizarding world into disarray.
Traditionalists: Both actual druids and new age. Limited on the selection of specific spells they dislike, no modern equipment or forbidden spells. They have easy access to natural beasts and spirits.
Progressives: Make use of modern technology wherever they can, believe it is high time to take the wizarding world into the 21st century.
Nonconformists: Those who practise the forbidden parts of magic such as necromancy and summoning outsiders, which they believe through study might benefit all, though many secretly desire personal power through any means necessary.
Loyalists: The powers that be, well equipped righteous bigots. Knights and inquisitors. Representing the powers that be, or at least were before the war.
And I quite like this setup. Every faction has some overlap with the others as well as topics they bud heads on. The loyalists and traditionalists are of the old school on most customs, remaining hidden and not using modern technology, but bud heads when it comes to the "status" of magical creatures and beasts such as centaurs and dryads. The rearing of magical monsters like gryphons is something the Loyalists like to legislate and the traditionalists would really rather not have anyone meddle in.
The modernists and nonconformists both are in strong opposition of the established order, rebels alike, but have very different views of what direction should be taken. Both also have feelings about the personhood of demons (like the imps) and vampires. The nonconformists have such creatures in their midst, but don't necessarily battle for their freedom so much as consider them both tools and/or potential allies in the quest for more magic (and power) They match the traditionalists in this way on the topic of magic natural magical creatures, but the traditionalists do not extend these feelings to the darker creatures.
And round and the wheel of alliances goes. See this I quite like and feel somebody smarter could actually DO something with.