If you build a big stack and use a mage general (Setsuna Sky for instance) then the crusade mode becomes fairly trivial even at the hardest difficulty. Seriously, Setsuna Sky is the real hero of the crusade. If they let him go on adventures he would curbstomp everything.
Oh god you just reminded me. This was another significant cause of my disillusionment with WotR.
I initially chose a melee general because I thought "war = fighting -> melee general should be well-suited." And I struggled a decent bit - fights were tedious, thought was required, my general's abilities didn't really help much.
And then I finally recruited a mage general, which made the crusade fights SO much easier. Just Scorching Ray (eventually fireball?) everything without having to worry about common non-magic DR of enemies. What a terrible game mode.
