Ok, now for something else.
Let's assume they didn't say "It's like a Thief", "you'll have the feeling than they came from thieves"...

What would a THF job offer ? Rogue is a DPS class, NIN is a DPS job. You want another DPS job from the same class ?
Stealth skills will be available for Rogues already, and all Thief usual assets (Evasion boost, Increased movement speed...) will also be Rogue's, since job don't have traits.

So basically...you want Thief for the name only ?