That made me think. If they show us this, then they must be confident enough in the quality of those particular dialogues. Which means that the rest is likely to be even worse... Please, do tell me my logic is faulty and makes no sense.
It really isn't.
Look at the gameplay from E3, the gameplay they wanted 'everyone' to see.
Now look at the gameplay from the Quakecon demo, the one they only wanted people there to see and didn't want leaked.
There is a clear difference to me between the two of them.
One which they wanted everyone to see and which they only wanted a select few to see.
Why is that?
The E3 one was pretty much staged gameplay, whereas the Quakecon one was a more hands-on kind of gameplay.
Publishers do this kind of stuff constantly, just look at a lot of triple-A titles and their screenshot promotional material. A lot of them don't even show the gameplay, they show staged screenshots taken from angles you won't see the gameplay in. That, to me, says that they are not confident enough in what their game really looks like when it is in still pictures, so they try to spice it up by making it look... Cinematic, I guess?
Regardless, just look at the E3 gameplay and the Quakecon gameplay.
The E3 one actually looks like an improvement from Fallout 3 to me (Ai, movement, shooting and shit) whereas the Quakecon one looks like Fallout 3 only marginally graphically improved.