Not so much a crossover event but I think it was a missed opportunity to have Absolute Virtue as the SS rank in EW. Using bene when health gets low, casting reflect on everyone while lowering their HP so healers will accidentally heal him. They already lifted so much from FFXI. For example, Ruminator is literally an exact copy of Cerebrator NM.

Otherwise, it would be nice to see a continuation of certain black mage that visited us once just to fight her again.