Jobs extend the classes and offer certain restrictions of their own. I was actually rather amazed to see people wanting to even retain the classes and not just convert them all to the most similar Job.

Whenever you add new stuff to the game, somebody just has to go "what if I don't wanna do that?" even if it requires minimal effort or is handed to them on a silver platter.

I sometimes wonder if the people complaining about class viability are unable to complete the job quests or something.