While i wouldn’t have anything against Swordsmen to have something against Magic i think making Guard also work against magic would be too much of an invincible-against-everything-button. Swordsmen need to have some kind of weakness, and while they are incredibly good against migating physical damage via evasion and block they are more vulnerable against magic.
Also, where is the gameplay skill and thinking involved if you can just stand there and be invincible against both physical and magical attacks at the same time?
If there ever should be a damage-reduction/damage-blocking way then i think it should go to a class that is currently rather underused and could need some buffs, like Peltasta C3 for example.
And if that’s the case then i think there should be no way to be almost-invincible against both physical and magical damage at the same time, these skills should cancel eachother out, like Gung Ho and Guardian, so instead of just standing there in incinvible-against-everything-mode the player at least has to be smart and switch buffs around, depending on whether he/she wants to block physical attacks or magic.
Also, i think Highlanders Crown skill already has an anti-magic aspect. I think it reduces enemies int/spr by 50~60%, which would be useful against high-int enemies.



