Whm had been my main in both FF mmos. Although I will be trying out sch, I'll probably end up a smn acn. They haven't released any info on the WHM job quest yet, besides what we can guess from 1.0. You'll will need CNJ at 30 and a sub class at 15, either THM or ARN, but we don't know which one yet. Its not a bad idea to lvl both since those are your subs for WHM anyways.