Putting arcane casters in medium armour is min-maxer BS, though. We're talking half-plate. Basically the idea seems to be that your arcane super-nerd decided to suddenly go out into the yard and play in the mud with the squires to learn how to move and jump and roll and parry and dodge while wearing fairly heavy armour.
Why not insist that your character is actually from planet Krypton while you're at it?
Half plate doesn't weigh that much and draconic sorcerers already exhist as more rough and tumble casters.
That's not to mention plenty of the wizard schools are used mostly for gishing
And what part of that stuff you just wrote justifies a bookworm being fully proficient with half-plate and such? Not really any of it, no? Which is as it should be, because wizards are not famous for running around in plate mail, be it full plate or half plate.
And we still have the problem that a dwarf with inherent armour proficiency is now suddenly a better pick for wizard than a squishy race that historically is much more likely to push into wizardry, whereas the dwarf has just about zero synergy with a martial class.
