Not base on weapon but base on their fighting style.
Zidane - Rogue (pure speed)
Squall - Drg (Gunblade's Trigger count as Burst damage)
Sephiroth - Nin (Mundra - Various magic spells)
Cloud - War (OP job)
Tidus - Archer (good mobility but not as fast as rogue)
Jecht - Mnk (Bad Ass)