New Vegas basically gave no forgets to the karma system inorder to enforce the faction reputation system thing.
infact the only thing that karma affects at the top of my head is whether or not Cass stays as a companion to you or not. if you lose too much karma when Cass is a companion she pretty much tells you to either change or go forget off. immediately missile'd her after she ditched me because first of all it was a Legion run.
Well in the old games karma in the old games pretty determined how npcs and followers might react to you as well as establishing a reputation status with various communities and how people might look at you.
I like the reputation system. For example killing a child gave you the title of child killer which made it so that npcs wouldn't even talk to you or want to join you and bounty hunters which would grow stronger and better equiped would be after you the whole game. Kill a whole town and twice as many good karma people as bad karma people and you earned the Bezerker status which made talking to good people really hard and bad ones even easier. Kill a lot of bad people and you become a champion, which just gives you a more positive reaction towards good karma people.
As far a karma is concerned there Neutral, Good, and Bad and just basically affects various little things. It could use some reform. For example one would think playing as a NCR character and stealing a map and set of documents called Legion Raid plans would make me a good person, yet it makes me a bad person. Like wise stealing a few sticks of dynamite from a few escaped convicts is considered evil.
I hope this game doesn't become too much of a shooter/action game, I still wanna feel like I'm just trying to survive, not take over the god damn world
Also, I hope there are hilarious but non-game-breaking bugs
I'm pretty sure FO3 is an action shooter when your man todd howard thinks murdering mass people to the sound of 50s music is both hilarious and what makes fallout a fallout game.