OK, capstone time!
I've had a couple of thoughts personally about this, and here's the ideas I've come up with.
1. Miraculous Reversal. (Su)
1/week the Sacred Scourge may make a special touch attack against any undead creature as a standard action. Roll a turn check as normal, opposed by a level check for the undead creature. If the creature fails, it immediately falls to the ground where it's former soul, and it's life are returned to it in 1D4 rounds. The creature comes back with 1 HP, no XP loss, and is considered to have had Atonement cast on them by a cleric of your level for the purpose of changing alignment. The target still gets a choice as to whether they chose to shift alignments or not.
I really like the idea of this, doing something truly miraculous which not only works against potentially powerful vampires and liches, but even 'saves' the target. The idea behind Atonement is that even an evil wizard-lich may be tempted to sway from evil once true life is restored to him/her.
2. Deliverance 25ft (Channel Spell)
1/day the Sacred Scourge may spend a turn attempt as part of the casting action of a touch spell he knows. He may deliver this spell to any number of valid targets through his Deliverance aura, meaning a heal could affect all allies AND all undead within the aura, or a bull's strength could affect all allies but ignore all undead similarly within the aura.
This was just kinda begging to be done after all. Don't think there are any MASSIVE exploits for this, but I'm putting ti out there now in case there is!
There's also the 3rd option (the 3rd thus far anyway!) of using your Disruption idea, although I'd be tempted to make it a Deliverance aura pulse, the class is kinda meant to have a last installment of Deliverance at 10th level anyway, so it would make sense. Let me know what you think anyhow.