I suggest picking Rogue/Cleric. I have few reasons for that.
Since rogue builds are pretty fast at movement, you can catch up traders and hunters (if you are thief).
Cleric would be handy at resurrecting/healing/buffing party members, since job war does not consist 1 vs 1 battle.
Therefore, crossbow has the biggest range, so you can almost always attack the player first, I don't talk about dagger crits.
Rogue/Cleric is not just good for job wars, he's good for a lot of things, for example CTF, when the opponent door is still closed - range does it's job here.
Anyways, just my opinion, a lot of builds are good actually.