p8 baal and chaos is not the end game. P8 TZ96 is. T5 heralds do require better stuff to kill efficiently. You need the mana from insight for mobility and you need high raw damage due to their high HP. His test is stupid again because he chose a setup where he is just seal popping, meaning he only has to kill 4 monsters total. Not sure why he would pick a setup where it didn't matter at all how well equipped he was-- his demonstration that he could clear it with a random weapon in the same time at the end proves how useless his test was.
I'm aware it's not the end game. But you shouldn't be able to kill any elite champion in one hit on p8 in hell with any build, regardless of your gear and regardless if it's in a tz or elsewhere—That's ridiculous. You can kill t4/t5 heralds using super cheap gear as well. Not exactly random shit you pickup but you can get by with using naj's for teleport or a staff you buy from act 2 and a few runewords and basic uniques you pickup, all self found within a few days of playing. No build should be like that, unless it's exploiting like a portal barb.
And yeah, I didn't watch the full video, but his test sounds stupid and he sounds stupid too.