Actually agonizers are a way better weapon than poisoned blades or normal power weapons. Wounding 2+ isn't that good if the opponent is allowed to take armour saves, and a S3 power weapon is by far not good enough to cause serious damage to T4 troops with decent armour save.

PS: I apologize for bringing an older thread back to the top (two weeks, so it's not that old yet), but that's something that really needed to be mentioned.