First off:

Does it really matter much in second job which skill you pick up? From what I have personally seen while training my bishop, lightning seems to be "kinda" weak while Ice Strike (I think that's what its called not sure) does a lot of damage, but does the mob-ability make up for the sheer numbers?

Second:

This is a more general question, but would adding more luk since magicians now have the High Wisdom skill you really wouldn't be losing out that much since isn't it an after % calculation since its just a bonus rather than a base stat addition?