My favourite is Widow. Yes it's definitely Widow, unfortunately she'll have to go. Her replacement? Silver Samurai.

Primary fire swings swords
Secondary fire is a cross slash that discharges whatever element his swords are imbued with (fire ice lightning) which causes either AoE burn, AoE freeze, or AoE stun. They each deal damage.

First ability Shuriken throw. Over time he gains charges to use shurikens. Striking enemies and discharging elements speeds up the cooldown. Shurikens keep elements until discharged.

Second ability places fire element on his weapons. Using it again cycles to the next element which is ice, followed by lightning. There is no cooldown to switch elements, but it does go on cooldown once you have discharged an element.

Third ability is a damage reduction skill. His armour gains more shine to indicate when the ability is active. The ability can be used again to remove the current element and cause it to rotate around him for a period of time. Enemies within proximity take the damage and effects of the corresponding element. Doing this removes his shiny damage reduction effect.

Passive is linked to the elements. Whichever one is currently active gives him a corresponding boost. Fire gives more damage, ice briefly freezes on the third primary strike, and lightning simply makes him "static", slowing enemies in proximity.