Basically Hawk's Eye is useless for BLM because it only buffs dex, which does nothing for our spells, and you should already have a 100% hit rate. If you dont, then you need more accuracy, as hawk's is only up ~22% of the time.

For Cross-Class skills, I stick to Raging, Quelling, Virus, E4E, and Physisk... Least Physick gives me a ~400 hp heal, still better than Hawk's.