I did a quick test using
https://www.youtube.com/watch?v=T6sB...59GtJ&index=11 - Keerarae's video on a Cliff Golem. I put a few more AC pieces on too just to try and get as close as possible. In the video he has 395 worn AC and a bit of buff AC with his willsapper + shield. I am doing an unslowed DPS comparison over 34 seconds, since it takes him 34 seconds to slow the Golem, and I don't have willsapper.
I had 352 worn AC and a bit of buff AC. I took roughly 34 DPS from the Cliff Golem over 34 seconds, vs. Keerarae taking 30.7 DPS or so. Obviously these numbers can be very swingy over 34 seconds (especially on a Cliff Golem), but it's a start. His extra 1 level and 43 AC might have given him about 10% damage reduction, which certainly isn't bad.
It isn't going to be enough to forego fear kiting, however, if you want to save resources.