I’ve always thought that the different elements should have a unique use case, to add more thought to build/gear. Wicked does a bit of this, but here are some ideas I had:
Lightning would be the area-of-effect (AoE) element which chains it’s elemental damage to nearby enemies, but has slightly higher on hit elemental damage to compensate for 1v1 situations. This would provide a higher damage per second option for faster attacking weapons and reasonable AoE damage for harder hitting slow weapons.
Fire would be the designated damage-over-time element, allowing slower attacking weapons to deal chip (dealing with very low hp enemy situations) and also burn down bosses during dodging sequences.
Ice already has a function of crowd control, but instead of just freezing enemies when their bar is fully charged, it could also slow them when hit. This would provide breathing room when there are multiple enemies to deal with, and even though bosses can’t be frozen, the slowed animations could be helpful. Pairing this with wide sweeping weapons would allow a player to instantly slow a large crowd, while fast attacking weapons get to the freeze and back stabs sooner.
Plague would be the “insanity” element; upon fully charging the bar on an enemy, they go berserk and attack the nearest entity, friend or foe. It would need something for 1v1 situations, so maybe a weaker damage-over-time effect compared to fire. It would be pretty funny (and somewhat useful) to force bosses into attacking your melee allies in multiplayer, though that kind of taunt effect could be abused for harassment. Same thing if this effect applies to players (since there’s friendly fire).
Having a specific role for each element would not only provide better reason to carry and use multiple weapons, but allow people to coordinate their builds in multiplayer.