I think it could be neat to see an Element locking armor, like Algern's Carapace or Svaldifari's oath, for each element. I quite enjoy these armors for the unique experience they offer and the added skill they get, it's a risk/reward situation since generally swapping to this armor will result in you taking a lot more damage but also being able to dish out a lot more as well!
Ive come up with a few idea for different special abilities each elemental armor
Fire: Special ability would be something such as x% chance to melt down the enemy's armor for the next turn or two and reducing their MRM or Increasing the element% (Thinking a decrease to the MRM would be a little more balanced though)
Water: Special ability would be something such causing the enemy to be trapped in a bubble without oxygen lowering their dexterity and perhaps another stat by a considerable amount while trapped in the bubble (I struggled coming up with a water themed effect so any suggestions would be nice)
Wind: Special ability would be something such as causing a bleed effect on the target due to how sharp the winds are or something along those lines, bleed would have all the regular attributes of any other bleed with a chance to save based on END and further attacks that have the bleed effect will increase the intensity
Ice: I had issues coming up with something for this that wasnt just a straight copy of Svalidfari's oath's stun to be honest but it would make sense for them to have a chance to be frozen solid (and perhaps take increased fire damage as a result? however that would defeat the purpose of an elemental locking armor...)
Earth: Chance to daze the enemy, giving them an x% chance to be unable to attack for an extended number of turns. (Similar to Svaldifari's oath, however this would be a reduced chance for act for a longer number of turns to compensate for that, potentially making it better or worse than the stun depending on rng)
Light: Chance to blind the foe, severely reducing their chance to hit
Obviously these are just suggestions and I am totally open to criticism on this but id love to get opinions!