[Taqwus]

ex -- if you're going to rely on cheap sacred troops, Order scale makes less since than magic for blessing. If you're going to pump out lots of regular heavy infantry, you want Productivity. And so forth.

And if you're going against elite troops that never tire (wights, for instance), or powerful mages, chaff may die en masse... whereas swarms will help reduce the impact of mindblasting, since mindblasting targets 1 unit per blast only. And so forth.