Raging Bards. Could be a good name for a rock band.
The information I'm getting here seems to go both ways. On the one hand Raging Barbs seems to help the human more than the AI because humans fight smarter, but...on the other hand, it's been mentioned that the AI has bonuses against barbs (I presume this means larger than the bonuses human players get) and thus, not only is the AI less vulnerable to barbs to begin with, but the barbs also tend to gravitate towards easier targets, meaning the human player.
So how large are the AI anti-barb bonuses?
EDIT: So I just checked the Civ5 difficulties page on this very website. It doesn't seem to be updated to the new AI default difficulty they use as of BNW, but I guess the values for the player should be unchanged. And it seems that not only do the AI bonuses against barbarians increase the higher the difficulty is, but the human's own bonuses against barbarians decrease with higher difficulty, thus making Raging Barbs on Deity probably a bad idea for the human.
Human players get a 33% bonus against barbs on Prince. That bonus goes down to 0% on Deity.
AIs get a consistent 60% bonus against barbs from Prince onwards, almost twice the human's bonus on Prince. Not sure if this bonus also stacks with the 50% bonus the AI gets from playing on Chieftain (pre-BNW).