Graphics aren't why I'm interested in this game; it's the open-world gameplay. So if the graphics aren't as great as initially promised, I can live with that, as long as the gameplay is good enough.
On the other hand, this is a cross-gen game. What will distinguish the PS4 version from the PS3 version? If the AI of NPCs remains exactly the same, then the graphics ought to be better to compensate. Otherwise what's the point of a next-gen console?
As was mentioned in the Arkham Knight thread, cross-gen development has got to stop. Otherwise, it will remove gamers' motivations for getting a new console.