This is why you never let a wizard (or an elf) plan battle strategy. A wizard just doesn't understand mass battle tactics beyond Fireball and an elf's racial propensity for ostentatiousness obfuscates reality. (IOW they are so full of themselves, they can't see the forest for the trees.)
Let this be a lesson, never leave the wizard alone, you never know what they will screw uppp, er ukp, I mean up.