Honestly i wish they would have had just a menu right from the start instead of making the weapon the way we change, that way it would be easy to let people use multiple weapons and not worry about it if they did change the classes around or add the job system.

Im gonna go ahead and assume its either 1) a menu thing, you choose when you equip 2) weapons will be specific to jobs or 3) if you equip a say "PLD" skill it will make you PLD and lock out w/e stuff you cant use.