As we all know, Bane of the Undead and Guardian Circle are master-level restoration spells that repel and incinerate* all undead up to levels 30 & 35. However, these spells have no effect on high-level Draugr and Vampires. I believe this a problem because the player ought to "get their money's worth" out of spells that cost +900 magicka so that these spells are less of a liability when facing Dragon Priests, Draugr Deathlords, and Nightmaster Vampires, and more of an effective asset.
In conclusion,
Bethesda, please increase the level cap of master-level restoration spells to +65 in the next patch.
*Incineration only occurs with Bane of the Undead.