I really do like the idea of taking a base weapon class like MRD (Axe user), once it hits R20, then you can quest training to learn either BST or DRK skills. So while you have the base of a MRD and you are learning to walk the path of a DRK, the MRD weapon class still ranks up and you earn job points to becoming a better DRK. Then if you decide to for go playing with other and want to solo, you can still take your R50 MRD weapon class, and earn job points towards becoming a BST. Your BST job is only gimped in that it hasn't learned all the new abilities yet, but as Job Points are gained then you rank up.

Introducing a few more weapon classes or adding weapons to existing classes (Axe & Scythe, Sword & Dagger, Bow & Gun, Wands & Staffs, Hand to Hand & Clubs, Whips & Flails, etc) and each one can split off to a new path.

But what if you just do away with MRD, GLA, etc, names and instead name the classes after the weapon? So you would be a Sword Specialist and from there you can train to become a SAM (Great Katana), NIN (Katana), PLD (enhanced swords like Excalibur for example). Axe Specialist to become BST, VIK (or actual MRD), DRK, etc

I guess I'm probably thinking more along the lines of FF Tactics. I really did like the idea of having a variety of jobs around that can really make it diverse instead of having everyone the same type of job. To me more variety can make up some really unique party play where we can really express they style you want to play with the jobs you create.

I think that was also the thing I liked about FFXI, there were so many different jobs that could be played.