I'm not really a fan of the Crystarium/sphere grid etc etc systems but i can see how it might work. Personally though i would probbably rather equip spheres/abilities/traits/what have you rather than be adding or deleting things on my grid for long periods of time like in X. So if adding/deleting things was bassically just equipping/unequipping then i could be cool with that depending on how they implemented it. This sort of system would have to be deeply rooted in each job because otherwise it would negate the need for classes altogether. This kind of system is largely used to do what the armoury system does or did.

SE should try to keep things simple and not delve too deep into creating numerous variations of a single job. I want to see Classes and Jobs seperated but it should be easy to pick up upon what benefits each Class brings to the Jobs.