Before we get started, I want to be clear that I don't think anything is "wrong" with Yrden or that the card needs a nerf. I've been on the giving and receving ends of Yrden before. It is what it is.
So, what's the problem? Why discuss Yrden at all if it doesn't need a nerf?
Here are the main issues people usually have with Yrden:
It can feel very sloppy, since it requires very little setup for sometimes enormous payoff. It also bypasses defender.
By resetting units, it "erases" the round's history. It feels too much like an undo button to many people.
It's highly binary, and can play for negative value in some matchups.
It hard counters certain deck archetypes like Nature's Gift, Arachas Swarm, and Kolgrim.
While I agree with many of these points in part, the case for Yrden is compelling as well. Consider:
Almost all decks have hard counters.
Yrden adds risk to excessively greedy strategies, such as turtling behind defender. The threat of Yrden forces people to play less greedily
Being binary doesn't make it a bad card. Plenty of other cards are binary.
Thoughtful deckbuilding can both maximize its value and minimize downside risk. Row movement techs and self-wounding cards can increase the upside and decrease the downside risk of Yrden, respectively.
I think the main problem with Yrden is that it makes people feel cheated. For example, I played devotion natures gift versus NR witchers a few months ago. I still remember the frustration when Yrden came down, erasing all the work I'd done. There was no setup or warning, no attempt to use Row movement. Just… Yrden. It genuinely hurt. The more I thought about it, what made me so mad was not the loss itself or the point swing, but the total inelegance of the way the card was played. There was no telegraph, setup, or counterplay. So certainly, I can understand why people are frustrated.
Here's my final verdict on Yrden:
Yrden should not be nerfed or adjusted in any way. 2 power and 11 provisions is already expensive.
Too much Yrden is bad for the game. Yrden should not be viable in most decks.
The best way for CDPR way to counter Yrden is to place more emphasis on non-boost oriented decks, and devotion. *cough SK warriors cough*
However, adding boost-heavy devotion decks will actually increase the prevalence of Yrden.
Yrden makes the most sense to include when paired with YennSwarm, Witcher Swarm, or possibly self-wound SK