I think the uniqueness of XI was the main/sub aspect of each class. Not only did this add uniqueness i think it could also add to the content side of things. I underdstand SE said right now there isnt any content out right now that requires cross class skills but this doesnt leave it out for future content. Ifrit 1.0 certainly needed it. Im not saying to add the main/sub thing into ffxiv put maybe get a 2nd slot for a soul crystal which will let u carry a few skills from those 3 classes. This can add more defense/evasion for a tank or even have a dps type tank. Mages with extra defensive buffs for critical fights. And same with dps classes having cross buffs. Some things would of course be scaled down so things wouldnt be so over powered.