Having to add custom code to for flash, their special form handling, and other Inertia specific parterns that only I really understood made it difficult for some collaborators. I don't remember the specific of the form handling either but from what I remember it would have been difficult to instrument client-side validation such as react-hook-form as well.
> The issue I have is the constant change of mind their devs have regarding how to do things, even when they say "it's stable"... it's not... every day they come up with "a better way" to do things which usually is not better, just different.
It is annoying. They are pushing people towards Remix as well, which I have tried and prefer to avoid unless I absolutely must have SSR. But their docs for older versions are still around so you can stick to what you like.