Fan service is definitely why XVI's Cid is also named Cidolfus and just happens to be the dominant of a thunder God. Well a thunder Ekion. Or why in E10 the background to that fight is X's Thunder planes. And actually that boss design makes a lot more sense. Not sure why it just took me this long. As Ixion is X's thunder Aeion/summon and so of course it got combined with Ramuh. All the while of being apart of a love letter to VIII.