Hooks shouldn't just be about "integration" with some other platform. To grow, SMF needs (IMHO :) ) to better support customizations within posts and topics themselves. For example, if I want to add an extra field to the post form.
That will not really be a hook, since adding an extra field in the posting areas involves several files. A hook, most of the times, is a simple line of code that appends content to an existing array.
Porting that idea to a form could be possible if such a form is generated via a form generator class, with a class if will be easy to build a method to add extra fields, you will just have to specify the parameters like the type, value, name and all that stuff. Of course this isn't possible with SMF at the moment.