Yes. All of the current Classes are merely stepping stones. The problem is the way SE designed the game the next Step has to be forced by the Player.
Gladiator is a Sword User. But he has a bunch of stepping stones he can take from there.
Equip Healing Magic, Defense Abilities, and Shield Skills. You are essentially a Paladin. You tank.
Equip Subversive skills, enfeebs, and situation damage dealing abilities You are essentially a Thief. You Subvert.
Equip A mix of Healing Magic, Elemental spells, and Damage over Time Spells along with your elemental weapon skills. You are essentially a Red Mage, You ... do what red mages do. I'm not sure what role Redmage ever fills they are a hybrid they can litterally do EVERYTHING which is why they were always so popular and why a 1 Red Mage (3 dead white mage) playthrough of FF1 is so possible.