I think what would be cool, and this would fit in with fort building, is that you could build a big wall across your kingdom, separating it from ....another part of your kingdom (o_O) to keep out the mongol hordes! XD
But yes, earth to dust is just ridiculous. the only one able to destroy your fortifications is you. Why they didnt implement this in the first place is beyond me, but hey, so is the fact they removed alch armour spells but didnt remove already existing armour
