To be perfectly honest, I agree with MAB-I know that if those witches dropped anything decent I'd go kill them anytime I was near cause it would be quick and easy, just a short step off the path for a couple minutes-sorry but it's true :/. Like people have said, the xp reward for them is pretty good when people of the appropriate level go against them and that's always a good reward. There's pretty much no loot to trolls in Har'Akir, but they're tough as nails and people go against them all the time anyway because the xp reward makes them worth it.