Rob Redmond has an interesting take on Funakoshi's relationship to the content of Shotokan, and its current practice, here...
Yes, now I can see it. But why did Funakoshi take out the crane stances? and the takedown?
This kata has pretty much all the moves of modern Jion AND Matsumura Rohai in it, intertwined. Fairly obviously, someone, somehwhere and when took this kata and extracted one set of moves to make Rohai and another set of moves to make modern Jion.