i choose those 3 element because compared to the other 2 elements, these 3 are weaker, especially arcane dmg, i hope with the addition of new set will make those 3 element worth to build, here it goes:
Arcane:
True Magic
applying arcane dmg to the enemy will reduce their arcane resist by 10% per rank while increasing your all resist by 7.5% per rank and your armor by 50% per rank of your arcane resist for 3 second
Ultimate Magic
casting MH special with arcane element cost all of the current MP and increase its dmg by +amount of MP used. also increase its AOE by +4 yd per rank. doesn’t work with push the limit affix
Ice:
Ice Age
each time you freeze enemy, create an ice field around that enemy. other enemy that step into the ice will be slowed for 10% per rank and have +5% per rank increased chance of being freeze. when you step on the field, gain +20% per rank of HP and MP regen. the ice field last for 2 seconds and is increased by 0.5 second per rank
Shock:
Wild Thunder
Strike random nearby enemy by thunder from the sky for 75% per rank of MH DMG each second. the enemy that get hit by the thunder will take 20% per rank more dmg from shock dmg for 3 second
Static Field
create a field of electricity around the hero that allow shock debuff effect to stack infinitely to the enemy that step on it. also, every 7 instance of debuff will create electrical explosion that deal 50% per rank dmg to the 2 yd per rank area around the target.
hope the developer will consider it too because these element, well you got the point about ice, but arcane and shock seriously need some power up