Hej it's me, the OP, after more than a year glad to see this is still garnering interest.
Please mods, as I cant access the mail on my first account, can you please edit the first post if other ppl post new locations?
I found one quest with Level 20 foes in HM that is fucking INSANE. It's the Am Fah quest Refuse to drink, you have multiple bunches of friendly Am Fah near a portal, when during the quest you refuse to drink they turn hostile, you wreck them, then if you rezone with the portal after they are friendly again and you can turn them hostile and farm them again (and again and again !!!). Rezoning takes like 10 seconds, THIS IS REALLY SICK, please add the quest to first post if you can, ty.