Took only about 7 kills for me ;p. Got it today and finished, final boss at ~512 gear level done in 30-40min judging by flask, like 7-8 wipes. Was gibbed by pretty much all things stated bar enrage (Felhunters eating enslave, enslave running out, forgetting to portal out of Chaos bolts) but in the end, it's very predictable fight, no rng whatsoever. Felt very similar to final boss of (stage 1) rogue legendary, more quest like that teaching people how to use whole potential of their skillbook would be really nice.