Good story and good gameplay do not have to be exclusive. The main distinction between games and other mediums of art is the ability to interact with the piece. We do this through gameplay, whether it be combat, minigames, or dialogue trees. A good game will use gameplay to reinforce themes in the story and the story is used to support the desire to play the game. Correct me if I'm wrong but I believe Josh Sawyer said something to this affect in one of the videos/interviews they've done.
Another thing is story is a lot harder to get across than gameplay mechanics. A good story requires building up, it's rather hard to show something like that off in a kickstarter update. I mean how would you show off the breadth of Torment's writing in a few paragraphs/pages? Would you rip out a scene from later on, something like Ravel or the Sensory Stone? It might be effective but you lose pivotal aspects, like the character you've built up over the game. How is this person you've been developing react to this? This is a bit in response to the Barbarian jab in the initial post, but the reason to get excited about new races and classes from a strictly story viewpoint is it multiplies the amount of ways your'e allowed to interact with the story, make it that much more personal. Maybe the Barbarian you make is a big dumb lug who wants to help out the only way he knows how, or maybe he wants to use his brawn to get undeserved riches. Maybe your Barbarian is well spoken and intelligent but after a life of trying to talk things out just to see people get stepped on and exploited he snaps, deciding that if they don't want to listen to reason he'll at least make sure they can never hurt people again.
I would love it if they would drop more info and ideas that they have from the setting, but there's also a fear in me of learning these interesting things before I have a chance to see them for myself in the game. Maybe it's just me, but I think part of the appeal here is Obsidian being allowed to really do what they want, and creating a world for us that will be large, fully realized, and inventive. I feel I can trust them to make this world one I'd enjoy based on the amazing work they've done on past titles.