I think it is pretty important since it's been a key element in other games. For example certain followers had a certain code of conduct for example some followers refuse to work with other Flash Mobing starfishs and child killers, others refuse or try to kill you if you joined a certain faction. In other cases being an starfish got bounty hunters sent after you, pissing off the wrong faction sends hit men after you. Basically it ties into choice and consequence.
The current system is better. Companions react to what you do (and I think only when they are present?).
This means your good-guy companion is going to be pissed off if you gun down settlers, but he's not going to refuse to join you because you were off alone, unseen, and happened to steal some crops.
The fact that you can get negative karma for doing actions no one saw is stupid and not immersive.
How would people know I am evil if no one witnessed my evil deeds?
And then there were petty acts that earnt/lost you karma needlessly.
Like killing ghouls in NV got you karma. Why would anyone care when I was just protecting myself?
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