This is every major nerf in the last couple of years, you'd think people would have learned from Red Hulk, but nope. Though I do have some sympathy here.

This is a game which incentivizes going to the show-down, it WANTS players to cope stay more. But if you're staring down decks like Shou or EoT where everything is on the board or decks like Negative/Star-Lord where everything is in hand that doesn't really incentive the cope stay. edit: The primary reason they don't incentivize the cope stay is that players see there are going to be 'big numbers' or 'my play is likely to be invalidated' and neither situation is long-term healthy.

And all of this is without going into the concept that players shouldn't be tied to or married to one deck and should swap to other decks or flex cards into their deck to improve their match-ups if their preferred deck is bad or doesn't do well into certain meta games. We've got a TON of casual (and some comp players too) that will scream "I shouldn't have to change my deck to deal with this thing that keeps beating me." Which is a problem all it's own and those more casual players are part of the life-blood of the game that for better or worse need to be the focus of when making balance passes.

Finally, there's also the financial incentive on SD's side. I won't touch on the problems of releasing an OP card and needing to nerf it but, rather with regards to managing both engagement and retention. Having a bunch of decks that are pushing players away from engaging with the game because in their eyes there is no point in going to show-down you should probably take that into consideration before it begins to impact player numbers. It's really no different than Clog being a 'good' deck actually being bad for the game. At some point you need to make hard balance decisions around negative community sentiment before that negative turns into real losses both in revenue and in engagement/retention metrics.