Crossbows were fantastic in Beta, so I made my girl a crossbow ranger. At the end of the game, she basically was just there to... well... maybe take an extra shot at the bosses I was melting with my two wizards and the two-handed GOD OF BATTLE that is Madora.
Seriously. Get resistances above 100% for elements, and you can just sit back and laugh at each battle. I send Madora into the middle of the fight, then spam the highest-level AoE spells I have, and stuff just evaporates.
And then my crossbow girl fires one measly bolt, just to remind everyone she's there.
On a second playthrough, I'd maybe try out the melee rogue skills to see if they're worthwhile. If not, a second warrior would be ideal.