As a conjurer I used Keen Flurry (LNC lv6) and [I forget what it's called] the lv2 ability for MRD that reduces damage by 20% whenever I draw too much aggro or the tank fails to grab some enemies. I normally just cross-classed defensive abilities for CNJ because they're available and it could really help for some bosses.

As for WHM, I haven't looked very hard, but since you need ACN for WHM and virus can be used by WHM, I've been using that. I could use get ruin and physik, but... I have stoneII and cure.

@Pentt How does one acquire swiftcast?