I actually thought that Thancred was alluding to something just like this in the storyline - you know after we saw the Doman fighter for 3 seconds and then had to have our eyes bleed as Thancred flipped around the screen for a full 20 minutes stealing her thunder? Really SE, why do you keep trying to redeem that weakling? Any why did we have to watch HIM flip around instead of the mysterious character we are all interested in learning more about?
I agree that Uldah would be the place for a thieves\assassins guild and it would be a secret organization.
As for why people are up in arms, for the final time I will explain: the more they try to NOT be Final Fantasy, the worse the game gets. 1.0 failed because it wasn't Final Fantasy, it was some other generic grind that didn't even make sense and no one recognized. Moving back to more of the same is counterproductive. What Yoshi-P really should do is leave the current class\jobs as they are, but going forward make each job its own from start to finish. There is no reason we need Rogue to evolve into Ninja or Thief or anything at all. Rogue can be its own class from start to finish. Ninja can be its own class from start to finish. Same with Thief, if they ever decide to get their heads out of their asses and give the players what they truly want.
There is no need for all of this "I was once this but I am now that and I have 2 level 50's listed in my character screen but I will only ever use the Job anyway". It's such a waste.