To tell you the truth, the fact that you need others to cover your weakness just remember me a lot more to the old FF you now, its kind of a good and nostagic feeling and I see no reason to change it.

But, the fact is, we have classes, and they are no where near to be weaker thant jobs, just less specialiced. And using classes you can be THM with ALL the elements or CJN with all of them.

WHM and BLM in FXIV are just made like they counterpart in FFIII. Maybe this decisions was made so CJN and THM wouldnt be one superior to the others, and both needed in fights. In fact, maybe even WHM should cast their offensive spell more often in battles where the have element adventage. It would add more deep to the class and making them more important and fun to play in some battle, but they will never overcome BLM in raw power and WHM would cast offensive spells just when needed.

But I deviated to much of the topic and I beg pardon for that.
I must disagree with you OP. Infact, I would like more complexity added to the wheel, a little like FFX, having monster nullfies, absorb, reduces the element damage or be weaks againts it, and not just one elements, they should have all elements in account. A boss or monster with total elemental resistence or right away inmunity, with crazy defense but low HP who need to be attacked with non-elemental spell like Holy or whatever non-elemental spell BLM have or could have in the future would be a new challenge to add, or a monster which need to be attacked with the right element to low they, otherwise imprenetable defenses so physical DD can kill it the possibilities are endless !.

The only thing that really anoy me is the lack of the water element. I make a theory about it but it still anoy me a lot >_<.