Potato salad shouldn't exist.
Yet, we live in a world where it does. (Sadly.)
Agreed. Where you can see this most is PotD. Stuns, Snares, even Roots (though not sure many Jobs have those anymore...maybe NIN with ice release?) work there. So does Sleep/Repose, and even ROG/NIN's hide/stealth. So do items to cure various status effects. Come to think of it, so do those status effects (things like Pacify, Silence, and Frog). Further, if you watch the people that really know their stuff, they practice arcane arts like...enemy spinning, where you rotate the enemy around and around to interrupt its attacks, or even...*gasp*...Line of Sighting, where you can run behind a corner to gather enemies or interrupt their casts and moves (like the beetle charge and ram thing or various spells that must be targeted which you can cause to fizzle if you can run around a corner from the enemy breaking line of sight).
Different agro types (sight, sound [RP walk prevents agro], proximity, HP damage/"blood", and magic [casting any "Spell" type ability causes agro - mostly seen on Sprites in Eureka]) exist both in Deep Dungeons and in Eureka (and I think Bozja, though less pronounced than Eureka, I remember the undead/ashkin in the northeast corner of the middle segment of the first zone having blood agro causing long chains of pulls if you weren't careful), and Eureka and Bozja play around with status effects a bit. So does a lot of BLU exclusive content, and I still go back to 3rd Turn of 1st Coils when I want to test if an attack type is piercing/etc or not (the minibosses there throw up various debuffs, so you can test if attacks are various types by seeing if the damage is reduced when they have the buff against those damage types: Fun fact, Fleche and Contre Sixte on RDM are still Piercing attacks!). BLU lists the attack types in their spellbook and some are useful for BLU Carnivale (especially going for the achievements/bonuses), but other Jobs still have slashing, piercing, blunt, fire, earth, etc damage types, even though enemy weaknesses/strengths against them have long been removed, as have player elemental resistances or abilities that increase piercing/slashing/etc damage. While meaningless in most modern content, the abilities still are flagged to their various damage types. One reason RDM is good in PotD is one of the bosses (floor 70 or 80?) summons adds that are REALLY weak to air type damage, making Veraero useful for making short work of them.
ALL of this stuff still exists in the game code, and is still active in various parts of the game.
It just isn't used in general content because...it would make it harder to balance and stuff and allow for cheese strats, is my best guess. Imagine if you could still sneak through dungeons avoiding trash packs entirely, like sections of Arum Vale and Longstop.
