The Job/Class system could start to be like Zantetsuken's overall idea to a certain extent. FFXIV should change the spells/abilities around on the jobs so that they aren't mixed around so much. (Example: Make CON have BLM spells and THM have WHM spells). Then change the names of the classes to match previous FF titles and the ability to unlock advanced classes by ranking up a variety of other classes. I also like Zante's idea of DoH jobs having an effect on unlocking certain DoW or DoM classes.
Because the lore is already set on thos classes and redoing the lore would be more trouble than it's worth to rename current classes to fit the "classic" classes.