I wouldn't really have a problem with these sort of things if they allowed you to get a discount for upgrading if you already bought the last gen. version of the game.
If you didn't buy the ps3 version, then $50 is an acceptable price. But for thoes who did, this stinks of double dipping. Of coarse I would agree that you can not single this game out, Tomb Raider or GTA V are just as guilty.