I don't know enough about which parts of the site you're referring to to say for sure, but stimulus / stimulus-like approaches are perfectly fine for most display-only views even if they're fairly complex.
There are pages in our app where stimulus works great and the UI is fairly complex from a standpoint of the number of strictly user facing behavior (click this, show X, Y, and Z).
The complexity involved in handling form UI is just not very suitable for stimulus from my experience. That said, you can still do a lot in terms of following good programming practices to create something that looks and works great and is reasonably maintainable.
It ultimately comes down to your (and your teams) tolerance and business needs - there's no hard reason we need to stop using stimulus, we've just decided that there are parts of our app where we could make leaps in developer productivity by using something else.
I built complex form before on financial platform where it contains complex investment details, different entities for different kind of offering .. with vanilla javascript. But that may sound grumpy old man in argument. Stimulus' weak point may be where it requires many DOM mutation per action, that's probably better use declarative way to re-render the whole thing in different way based on data.
Not at all - I still favor vanillajs if only to avoid the bloat of the whole modern js toolchain (webpack...babel...extra compile times)
There's also a big difference for us within the form world between forms with ephemeral state and forms that need to persist state through many interactions and sessions. The former is perfectly fine for us to handle with vanilla js, the latter just becomes easier for developers with a declarative model.
There are pages in our app where stimulus works great and the UI is fairly complex from a standpoint of the number of strictly user facing behavior (click this, show X, Y, and Z).
The complexity involved in handling form UI is just not very suitable for stimulus from my experience. That said, you can still do a lot in terms of following good programming practices to create something that looks and works great and is reasonably maintainable.
It ultimately comes down to your (and your teams) tolerance and business needs - there's no hard reason we need to stop using stimulus, we've just decided that there are parts of our app where we could make leaps in developer productivity by using something else.