I feel that the flaws in relying on tainteds for your damage are really apparent here, in that it's monstrous single target damage, but the lack of a defiler/big splash damage is really noticeable because so many monsters are left surviving.
In this patch, with how heralds function, you'll miss a lot of heralds by missing so many mobs, and having to stay to clean up slows everything down. From watching that video, I feel just the straight blood boil I was running last season would clear that zone faster because every monster in the pack is getting clipped (either by the boil itself or by being linked with the defiler) and there's no reason to have to go back to clean up.
For example, that really low-hp pack at 1:02 required 6 telestomps to kill, and there were mobs left behind. I have to imagine that a 125 fcr obsession blood boil build would have had that done in fewer clicks and with faster teleports.
There's definitely no comparison when it comes to killing a boss/high life mob, but if you're spawning fewer of them because of the way the build works and having a playstyle that leaves a lot left behind, then I think the tradeoff isn't there.
There's not much point to chasing down every non-unique mob and tainted are autokilling about 75-90% of them just by teleporting past them without even clicking on them
You reach an upper limit of clear speed where you need to slow down to actually see items drop and teleport back if you missed them. Any build that has to stop and cast spells, let alone aimed spells, can't approach that. We had blood boil being faster than ES in patch 3.1 because you had to actually click ES on mobs but blood boil was just teleport, cast a few times unaimed, pack dies, repeat. But taintlock is approaching something we haven't seen since the aurasorc / auradin stack glitch of patch 1.11. I am simply holding down my teleport button until I run into heralds or some big packs of fire immunes worth killing. I can clear a whole act in the time I see people dicking around in a single zone.
To give another example video, I just saved some footage from a pub run. If you click on any random timestamp, it shows what I mean about
clearing at teleport speed rather than stopping and casting.
I have a 125 setup in stash, and I'm using a mang songs just to prebuff, I could have higher damage blood boil or higher FCR, but to what end. If I go any faster I can't even pick up items. Obsession is a QoL improvement over Mang Songs at the cost of DPS, but here I clearly don't need DPS at all and you can see how unplayable the mana situation would be if I wasn't regenerating nonstop, even 500 mana + meditation is coming close to draining my mana at points and the only spell I'm casting is teleport. I mean maybe there's some absurd setup where you run so many +skills you reduce the mana cost on teleport enough and stack mana regen for the rest, but insight does it on its own.