FFXI had elemental resistances and even general damage type resistances as well as an MMO which would effect party compositions depending on end game activity and even preferred exp locations for lvling up or earning merits. However it still didn't completely exclude jobs from content. However jobs in FFXI had more options. BLM, RDM, and SMN had every element available for magic. Physical damage jobs had weapon options that could change the type of physical damage they dealt between slashing, piercing, and blunt. Something we don't have in FFXIV. That said job specific traits and implementation of damage resistances would atleast shake up the end game "meta" making the ideal party comp change depending on content. As it is now jobs are chosen over others anyway for other reasons and that's always going to happen. The difference we have now is those reasons are the same for all content of that type.