So from my perspective this set bonus is extremely underwhelming. The only thing i want out of the set is the 2nd charge of AoE taunt, which while it has uses is weaker than lord of pain which i already think is a stupid design for a set due to it being focused on AoE taunt hitting multiple enemies. If it is a boss you are tanking the set feels useless, but back to the new set.
4 piece: 2 charges on AoE taunt feels like a quality of life improvement for flashpoints and maybe certain bosses in Dxun while not being worth sacrificing the damage reduction of lord of pain for those fights it will make tanking the trash easier.
6 piece: This is the part that i think a lot of people misread/misunderstand. This is a extremely weak set bonus, it doesn't turn your endure pain into a good cooldown. Internal/Elemental damage types are extremely rare and often chip damage and dots, in Dxun there are some things that are bursty that this would work on but that is it for this set being useful in ops. It is a reward from Dxun, to make Dxun easier.
To give examples of how this set bonus is weak in previous operations let's go boss-by-boss in machine gods.
Tyth: Guardian explosion and Justice shield are I/E. One is a type of damage that most people don't even realise is there and the other is avoidable.
Sisters: Radiance, dot from the middle beam in the first phase. Radiance hurts but is it worth a 10% damage loss or 10% dr on aoe taunt? Doubt it
Nahut: Mostly his first phase damage is I/E along with the final burn. Maybe useful but a lot of that damage is bad due to it being AoE damage so 1 person taking less damage will not achieve much.
Scyva: I'm not even sure to be honest, it will not help with the turrets which are the main part of the damage in the fight. Most likely small chip damage from purple in the ground or the red spheres.
Izax: Tethers and blue puddles, useless.
The point i am trying to make is that Force/Tech does not mean Internal/Elemental, a lot of force damage is energy/kinetic to make it shieldable. Most DoT effects are internal/elemental though, so what this set achieves for the most part in old operations is avoiding DoT damage for only 3 seconds, the only good use in old operations i found were the first 2 bosses in Explosive Conflict that have a boss that is purely I/E damage so you can mitigate a couple basic attacks. And if you are thinking i am wrong with this, i ask you to think of I/E things in ops that kill you as a tank first. The game does a bit of a poor job explaining the differences between these damage types to players which means without 3rd party programs for help you often don't have any indication of what is F/T and what is I/E damage, which i think is why people think this is going to be a good set that makes our worst cooldown better.