In fact, to prove that I'm not just talking the talk, but that it's actually very easy to at least imagine a whole new skillset for a new jobclass, let me present to you three new skills that I would see implemented for a Ranger:

Weaponskill: Deadeye || Cast Time: Instant || Cooldown: GCD
Delivers an attack with a potency of 190.
Can only be executed after inflicting critical damage.
Additional Effect: Increases critical hit ratio by 5% for 15s.

Ability: Lethal Bolt || Cast Time: Instant || Cooldown: 25s
Delivers an attack with a potency of 150.
Can only be executed after inflicting critical damage.

Weaponskill: Deadshot || Cast Time: Instant || Cooldown: GCD
Delivers an attack with a potency of 170.
Can only be executed after inflicting critical damage.
Additional Effect: Damage over time with a potency of 25 for 15s.