You know what else I miss? They used to break the patch pattern a bit at the end of each expansion X.5X.

Late ARR added the Gold Saucer and the Odin fight that drops his glam.

Late HW had the most experimental stuff. There's the weekly goblin quest which gives unique accessories of an item level equal to that expansion's savage and augmented tomes.
Also the v2 remake of diadem which had a raid in the middle, dropped ultra rare weapons which were 5 item level higher than savage... causing the parser people to complain that RNG loot prevented them recording the best scores on their 3rd party parser log site. They were called Coven weapons, IL 280.

Late StB had Baldesion Arsenal and the fake Yojimbo trial fight, also a bit earlier was the Monster Hunter crossover trial which has some mechanics not usually seen in ffxiv.