In May we got announcement of Baron Zemo and Absorbing man balancing updates.
Dev team stated that they are aiming to change his furies that he gains from purify/immunity and armor up buffs that act as cooldown of cleanse passives. With fury buffs they simply wanted to add cap of 15.
Armor up on other hand should've been changed from Buff to a Passive and reduced its duration to 15 seconds.
They also stated that "With the idea of it being changed to a Passive, we’re also exploring what type of defensive effect best helps Zemo as a Skill attacker."
Its August now and we got patch notes for V41.0, where balancing updates are coming into force for both champs.
I followed updated champion spotlight to check for the changes, and what do i find?

Indeed, now its duration is 15 seconds. And yes, they said that they are exploring new effect for Zemo instead of armor up.
But there were not a single word about new effect having its POTENCY REDUCED.
Previously, 6 star rank 5 could get armor up buff that would increase his armor rating by 9000. And now its resistance up passive of 2250 potency.

(information from
https://auntm.ai/champions/baronzemo/tier/6)Of course directly comparing potency or armor ups and resistance up effects is not exactly mathematically correct from point of game mechanics and implications (like the fact that resistances can influence dmg taken from dot-effects that do energy/physical dmg). Yet it is drastic decrease in potency, and ANOTHER NERF for Zemo.
This change will make him significantly less tanky both on attack and on defense once his cleanse charges run out. There was not a single word in balancing update about dev team wanting to reduce his survivability.
Just couple of weeks ago we got silent root nerf, and now this?
What's even the point in ranking up champs at this point? To wait until they will get "bugfixed" and nerfed to the ground?