1. In the beginning, classes were homogenized, and the line between roles was blurry, at best and nonexistent at worst. Each Mage could heal, nuke, DoT and Enfeeble. Each melee seemed a lot like the other melee classes. Gear seemed to have very little effect. Balance gave way to chaos. A change was definitely needed.
2. Jobs were promised as a way to bring more structure. A defined system that was to be the perfect compliment to the Amorphous Armoury system, which, despite it's flaws, had so much potential.
3. In the updates leading up to, and including, 1.20... Classes receive a major overhaul. Classes are now much more defined. Conjurer HEALS... thaum Nukes, Glad does shit damage but tanks. Lancer builds TP fast and fights at a semi-ranged distance,. Etc.. These changes effectively did what we thought jobs would do, and while some of them were needed (Thaum, I'm looking at you), these changes really eliminated the need for jobs
4. The Job system in FFXIV is released and is a great misconception. Jobs are not more specialized play styles than the classes from which they stem (With the exception of Barcher). In fact, the role of each job is exactly identical to the role of each class (Once again, except for Barcher) as was established in patch 1.20.
And now the problem with this entire argument
Neither side can get what they want.
If you want multiple Jobs per class then you are out of luck. Each class does one thing. If jobs are an extension of that, then what could possibly be the second job for a Thaum? I know you are going to say enfeebles or DoTs... but Thaum doesn't do that now... You'd be stuck with one job that IS the class and another job that is contrary to the spirit of the class. If they wanted Thaumaturge to branch into both a Nuking job and also a DoT job then thaum should have retained some of its low level DoTs.
PLD is a Gladiator... any other class that stems from Gladiator would have to be completely contrary to what a Gladiator is.
Same for WHM coming from CNJ. What would you have Conjurer become?
It would look like this:
Conjurer is a healing class.... It branches into 2 jobs... one that heals and another that heals
Conjurer is a healing class.... It branches into 2 jobs... one that heals and another that has nothing to do with the idea of Conjurer at all
If you want one class for each job then you are also out of luck. The Armoury system (Which is the cornerstone of the entire battle system) dictates that each class is designated by a weapon. To suggest that multiple jobs can use a sword, for example but not be based off of Gladiator would cause the armoury system to breakdown much like Norman did in Star Trek upon hearing the illogical phrase "Everything I say is a lie"
Each class is designated by a weapon. Which means you can't have 8 jobs that use swords be based off of 8 different new classes.
Yoshi-P and crew have painted themselves into a proverbial corner. I am actually anxious to see how they get out of this one