Sounds like a whole complicated mess to me. It's like patching a wound by inventing a system where you are patching bandaids in complex patterns.

The make a boat out of duck tape analogy comes to mind. It really doesn't solve much of the basic problems.

How would people switch back and forth? how would they properly allocate their traits and skills? How would the stats combine and detract.

It's like the physical level problem, you end up getting over balanced and make it not matter.

It's just...complex.

And frankly it's not all that different from FF11. With weapons skills giving WS and job levels handling skills/traits.

All the proposal really does is spawn tons of combinations in an attempt to hide the existing combinations.

If such a radical change is wanted, there are tons of better way then to graft it onto the existing armory system.

A better way to do 2 tier system again is to eradicate the armoury and skill system again.

Audit all the existing skills, and then group them into 2 groups: Weapons and Jobs. And Done you have your system. Of course when I explain it that way it sounds horrible generic...which it is.

I see a lot of solutions are basically trying to add complexion onto the existing system in an attempt to hide the problems. That's a self defeating formula.

The best way to reinvent the job system is to either re-organize it, or scrap it for a new one.

IF you really want this proposal to work...
A hard line has to be drawn after auditing and revamping every skill

Weapon type = skills
Job type = traits

Let's say you want...

bow welding blackmage an ARC/BLM
Arc would have quick knock, mult shot, etc
BLM will provide
elemental damage increase
Elemental enchanting of regular arrows (cool down)

This would of course do away with the armoury system and the skill system pretty much. Even if you do allow some cross skill equipping, there is too much potential of repeating the same "super class" over and over again.