Very interesting analysis.
However, don't you need the moon to become Oozaru? So does that mean MSSJ Oozura wouldn't need the moon?
If you look up wiki, it does say
'The Super Saiyan 4 was designed by Toei artist Katsuyoshi Nakatsuru, and was designed to more closely resemble the Saiyan Ape form which appears early in the written series.'
Maybe they thought that the manga had gone too far away from the orginal ape/human idea (super sayain has nothing to do with apes) So they wanted GT to go back to its roots?