> eliminating this call would break backwards compatibility with the usage of 'init' as the only action

But pre-1.0 code wouldn't use the `fm_register_submenu_page()` function, it would use the `add_submenu_page()` method, right? So unless I'm missing something, that could be rectified.

If it would mean inconsistencies in implementation patters of contexts, that's enough of a reason for me. Consistency is key.