Thief should be a subjob.

[BlaiseArath]

I suggest a challenge!
Make a Thief Job with the 5 allotted skills all jobs get (minus any set up skills like Ninja's Mudras) using Rouge as a base, that isn't a carbon copy of Ninja.

Hmmm... I think it could be done. NIN gets its uniqueness from Ninjutsu, and while its true THFs abilities have been spread out over ROG, there could be a few things added.

Despoil - An attack with a potency of 100 with an effect that varies based on position.
Front: Inflicts Slow+20%
Back: Enemy damage dealt -10%
Sides: Inflicts a DoT. Potency: 40 Duration: 30s
Recast: 120s

Kiss of the Spider - Increases damage dealt by 15%
Allows Sneak Attack to be used without the aid of hide, but triples its recast time.
Shares recast with Kiss of the Wasp and Kiss of the Viper.

Rudra's Storm - An attack with a potency of 100.
Combo Ability: Gust Slash Combo Potency: 250
Combo Effect: Inflicts heavy gravity effect on target and reduces is
accuracy and evasion. Effect duration: 15 Seconds

Evisceration - An Attack with a potency of 100
Combo Ability: Mutilate - Combo Potency: 200
Combo Effect: Inflicts a DoT with a potency of 40, Evisceration has
an increased chance to critical hit when on the targets flank.
DoT Duration: 18s

Collaborater - Reduces the enmity level of target player by 25%. Increases
your enmity level by the same amount.
Recast: 120s

Ambush - Delivers an attack with a potency of 250 with an effect that varies based on your position.
Front: Enemy elemental resistance -10%. Duration: 15s
Sides: Player Critical Hit rate +10%. Duration: 15s
Back: Increases potency to 450.
Recast: 300s (Their final ability)

I mean, every DD is kinda a carbon copy of the other. You have your basic 1/2/3 set, your DoT/combo off set, and a few other unique things. So yah... positional stuff kinda sucks but it works for MNK and if done right is pretty awesome. Also, I wanted, for obvious reason, to name "Kiss of the Spider", "Kiss of the Shark", but... sharks aren't venomous ;; ... These are just ideas that were spitballed to show it is possible to make a THF job thats not a carbon of NIN.

HOWEVER - Its not to say I want that. Personally, ROG/NIN is good for me, I love the THF class in pretty much every game I play, I enjoy i thoroughly and in XI it was no different... NIN fills the THF void for me just fine, so I don't necessarily think THF needs to be added, but I'm saying it probably could be done.