It's been the same for every version the last year.

Oh, this Opus X.Y is incredible. Hmm... Now it's dumb. Rinse, repeat.

Doesn't really matter if the cause is quantization, system prompt changes, changes to thinking etc.

It's hard to see how continuously rug pulling users at every release is a good idea. Only reason I can fathom is that it's needed to keep costs inline.

Either that or it's some weird tweaking to the prompts to fix whatever. But given the prevalent sentiment that it's worse that sounds like a long shot