Please don't twist the point I'm trying to make Jinko.You saying this doesn't happen already ?, since when does a CON tank ?
This new system of progression seems reminiscent of FFXI, but at the same time is very different. As much as everyone hates comparisons, allow me an example if you will. Paladin.
In FFXI, Paladin was an advanced job that required a previous basic job at level 30. Prior to this point, warriors were usually the ones to do any serious tanking in a party if I'm not mistaken. Past that point, however, Paladins were undeniably the better tank. (This is looking solely at the job itself, putting aside outside factors such as Lv 74+ Ninja subjob, etc.).
In FFXIV, Paladin is a job that requires Gladiator (a class) at level 30, and Marauder (a class) at level 15. Prior to this point.. I'm actually not sure, its pretty touch and go which one is the better tank to my knowledge as patches have made things touch and go, but past this point, Paladin is a specialized role that should undeniably better as a tank than the Gladiator or the Marauder, this is its specialized role.
Is this ok so far?
In FFXI, despite the fact that a Paladin is obviously first choice as a tank, the basic job warrior is still viable in its own right in a party at higher levels. In FFXIV, this apparently no longer going to be the case as the community obviously seems to only want these Jobs in a party, and classes despite their versatility will no longer be a viable option on their own in a party situation.
This, of course, is all just my opinion on how things are turning out.
Edit: and I noticed you edited your post but, yah... :/
Edit again: Looking at this new system as a whole, and from what I recall from the interviews regarding this system, the Jobs were supposed to be a specialized role in contrast to the mixing and matching that we've come to know in the Armory system. However, having made many traits / abilities exclusive and limiting the amount of abilities that can be mixed and matched, the classes themselves feel to have become specialized roles in the process, defeating the purpose of the specialized Jobs. Personally, I think it would be better if they just scrap the system and have only jobs at this point.