Relic weapon black mage why no 1 hand

[saeedaisspecial]

1h + Shield is bad.
It generally results in lesser stats during progression when gearing up (because going from ilevel X weapon to ilevel X+10 weapon while your shield stays ilevel X results in less stat gain.)
It also generally results in mixed/non optimized stats, such as the Leviathan Shield/Wand (and PLD's HA Sword/Shield combo, too) which basically had little bits of everything instead of two full stat allotments, which is almost always better.