I know there are a many posts about this already, but bear with me.
So from what the dev's have said and what for all we know there isn't gonna be character levels gained from EXP. And Weapons it sounds will be our way to progress in game.
Gaining skill levels with weapons might give us our "Job Abilities" or "Magic Spells"
what if weapons and equipment came with stats attached to them so like if you wield a sword you get: +5hp +2mp +5 parry +1str. a skill level. a wand you get +10 mp +1hp +5mnd +5int. a skill level.
Of course differnt weapons of the same catagory will have differnt stats on how you want your character to grow. Normal weapons will give you certin skills as you level.So maybe "Rare" weapons will accually allow you to learn a "Class defining" skills. like maybe if you gain level 10 with a polearm, you visit a NPC who is a polearm trainer and he gives you a quest to find a legendary dragoon spear. if compelte said quest and you get to use the spear. it allows you to use the "Jump" skill and you are able to learn it for good if you use that spear enough. Sort of like unlocking the latent effects on weapons in FFXI.
If this is a possibility we'll be able to mix and match jobs to our liking. WE'll be able to wield a sword and shield, cast curing magic, and maybe sneak attack. If we used the correct weapons to gained said skills.
So we still have the job system in place, but works differntly then FFXI. of course the weapon you are weilding at the momment might hinder you from using certin skills to their maximum effect. Like using a DD type weapon. ie Greatsword, Scythe, Battle Axe. Might give you -mp per skill level, or very few. SO you can;t be a DD + healer at the same time. In the same respect you can't be a healing DD either, unless you go the magic route. Or possibly you are able to slot a certin amount of "extra skills" outside of your current main weapon choice.
Just an idea i've had rolling around my head the last few days.