That said, aiki as I know it (from two separate lines of aikijujutsu and from one Chinese internal martial art) is the intent-driven manipulation of a body state that we create and manage. Therefore, when you move with an "aiki body," it will manifest itself in everything you do, whether kata, applied technique, or free-form "street" combat. It remains, then, for the individual to develop the skills -- formal/kata, waza, combat -- so that that they will be able to serve as sound vehicles for the aiki engine that will drive them.
What, in your opinion, accounts for the lack of practitioners who can truly create free flowing aiki, then? Why should there be such a plateau?
If one must develop "application skills" as a separate study, then doesn't that mean those skills are attainable by themselves, with no prior requirement of internal power? If so, could there not be some value in pursuing them directly, and forgoing the internal skills altogether?