I think noctis' point is, and i'll try to sumise;

Class - multi functional and intended for low man groups to cover a wide array of variables
Job - dedicated roles where each member is a valuable and unique asset

If Square Enix implement jobs in a way where classes are still required to clear content because of their sheer utility belt array of skills then the implementation of jobs has failed.

Its not that we shouldnt use them for strategy molly, its that the strategies that involve all jobs should (no pun intended) out-class them.