Thanks to the improved hardware in the PlayStation 4, we'll be able to witness a whole lot more in our gameplay than the PlayStation 3 previously allowed us to.
One good example of this is in infamous: Second Son, a game that Sucker Punch has recently revealed will be capable of keeping track of the things you destroy in-game, meaning that when you come back, that damage will still be there.
This new capability is possible largely to the GDDR5 8GB RAM found in the PlayStation 4, which is miles apart from the PS3's tiny 512MB DDR3 RAM.
Sucker Punch has said "it was very difficult in a PlayStation 3 timeframe, where you don't have enough RAM to store information about every object in the whole universe. The areas would just be refreshed when you leave and come back. But now we have a lot more to work with."
Personally I think this is great progress for gaming and I can't wait for InFamous: SS.