I would like to know which weapons you are specifically referring too because in past FF's Dark Knight was always able to use hand axes, two hand axes, swords, shields, great swords, spears, clubs and dark swords and eventually Scyths(Which came last and never again in FFXI).
While paladins were always able to use clubs, swords, shields, great swords, lances, poles(combat staffs), hammers, and two handed hammers, Bows?
Hell. Dragoon? Lances, Polearms, Swords, Wings Swords, Epees, Clubs, Staffs, Shields, Anchors and Harpoons.
Oh Wait, White Mage. Hammers, Clubs, Shields, Poles(Combat Staffs), Caster Staffs, Rackets, Two Handed Hammers, Fists.
Oh god, I can't forget Samurai. Katanas, Mystic Swords, Dark Swords, Great Katanas, Polearms, Lances, Shields, Scimitars, Clubs.
Wait a second... Thief?
Daggers, Swords, Scimitars, shields, Fists, Fencing Swords, Clubs, Throwing Weapons, Bows, CrossBows, Guns.
Corsair/Gambler/Entertainer? Dice, Cards, Darts, Guns, Rifles, Daggers, Swords, Harps, Flutes, Bells, Their Voice.
Puppet Master?... A Megaphone, a Remote Control, and a Marionette Cross... As well as fists. Oh Puppet master loses out I'll admit.
But 95% of the time in Final Fantasy No Job is limited to ONE weapon. And thats encompassing over 50 different games and added materials.