I disagree with Droylt for the simple reason that my players don't like spellcasters so i've never found a problem with any of the Disciples in play as villains.

They may be middling to low 4th tier but they're backed by extraordinary flavour and if actually used per their MO in game, are still a threat as long as you've not got powergaming in play. I'm sure they do crumple like dust-bunnies if used head on but that's really not their point.

Redo them if you like but please, emphasise the cult/exemplar of bastardry aspects over straight up combat potential.