tracking the fired event on form submission is a very good first step like it's described in the event tracking tutorial
But don't you think the road is the true goal. Hence, knowing how the form is filled out by firing events to track the goal funnel would be awesome. I checked the controller.php but the "on_sent_ok" functions can't be utilized.
Does anyone have an idea how to implement more additional settings in the form configuration so a GA onClick event is inserted in the fields? Firing validation error events might also be a necessary.