Indirect fire

And instead, the stepper's being put onto the third Castigator.

Yes, because everyone loves Indirect Fire and Exorcists, don't they? So now the vehicle heavy build is two Exorcists, two Castigators, rather than three Castigators, one Exorcist.

The enhancement you can give to the Exorcist is a unit enhancement, so you can give it to multiple Exorcists.

So yeah, now everyone's got to deal with two Exorcists in their face.