If you play a somewhat neutral to evil character roleplaying wise, you'll get the following:
Three thief guild quests, although I thought it is funny how Umar ignores the fact that I just failed his brother's attempt to free a thief from jail by siding with the guard, and still offers me to join the thief guild
Eowyn's ring (debatable of its usefulness)
Marrowtaint necklace,
Xul"viir,
Dark protector.
They gives long-term advantage in the game play. Short-term ones like extracting more money in some quests.
However, if you play a good character, you only get extra xp once in a while.
So, unless I am missing something else in AT, being bad boys (or girls) pays in this game.
Not really. But you conveniently leave out is the benefits of not getting the dark protector. Or not getting the marrowtaint. as not getting that necklace get you access to the only item that provides a critical hit increase in a certain item category.
As far as the thieves are concerned the immaculate kidnapping quest will have consequences I guarantee you that.
This game is all about the consequences and paying for your decisions and choices.
There should be consequences for choosing either of the side, be it bad or good. It'll certainly make the quests more interesting. I love C&C type quests and storytelling a lot. The game does present some amount of C&C but I am always greedy for more such experiences to be included in the game.
I am sure the developers have plans for projects related to Nor city, and others in the pipeline. It might raise the ante for the decisions we took in the present time.