Here's the thing, unless they make the second job the same role, they'd need to make new weapons for the new job anyways because of role specific stats like Tenacity and Piety, and largely a new set of skills outside the basic weaponskills and/or spells... The only way it would be easy and functional would be doing something stupid like taking Gladiator and making it become 2 different tanks.

If you wanted to turn it into some other role, like DPS, you'd need to take replace basically everything except the Weaponskill combos...