The quests in Fallout 3 were anemic and about as deep as an outie-belly button, not enough depth to even gain lint.
I'm hoping to have a nitty gritty wasteland feel where the factions go for each others' throats.
Imagine in FO3 if eradicating the Talon Base was a quest, but only after extracting certain 'moles' that were placed there, and finding vital intelligence that would corrupt itself if not gained through subterfuge. Or being tasked with eradicating the BoS by the Outcasts and securing outposts around the wasteland from the BoS as well as creating new ones.
There seemed to be so much potential in FO3 that was wasted - the characters were all in place, the locations, the factions - and then, nothing. No quests, no goals, no tension, no change in the world.
So.... that is probably my number one hope for New Vegas. (and Fallout 4)
J