I think this should be added, although Guile doesn't (yet) have it.  It allows the construction of a hook without messy mutation.

Given that, list->hook! also makes some sense ("keep the hook, which others may already know about, but throw away all the procedures and use these").

It would also be nice to say that in a Scheme with invokable objects, hooks should be among them, so that you can invoke the hook directly.