Well, i finally read Jojo's Part 4, and i must say, Okuyasu is a lucky son of a bitch, in a world where the closest sidekick of the protagonist is practically guaranteed to die (Will, Ceasar, Kakyoin, Bruno, Hermes, Gyro and possibly someone in Part 8) the only one who didn't died was Okuyasu, and hell, i don't know if his reappearance in the final battle against Yoshikage it's considered something lucky or just a Deus Ex Machina (Like Jotaro's Star Platinum + The World) for the protagonist.
Josuke managed to put up a good fight, but there was some things that were untouched by the end of the series, for starters, what happened to Shizuka after Part 4?, that invisible baby remained remained as a mystery after that part, not only that, is the nature of Mikitaka, Stand User or Alien?, given that nobody can control that well a Stand if a person was pierced in some hours, and since he can create ice creams from his finger nails, my guess is that he is an Alien, a funny one, but an alien, just think about it.
Yoshihiro couldn't pierce him, he can't see Stands, and his allergic reaction to sirens (Where he has an unnatural face during the reaction) all points that he is an Alien, but that's just my bet though, and one last thing, Yukako was horribly useless in the plot, not saying that her stand was the hot shit, but she could care about the Yoshikage's case since he could have killed her, hell, Rohan Kishibe was practically the only who came really close to notice the fact that Kosaku Kawajiri was in fact, Kira.
But never mind, i can't blame a teenager in love, hell, if it was for that fact, Josuke, Okuyasu and Koichi didn't put too much of an investigation, instead, the enemies approached to them, and once beaten, they could ask about that information, it seems that Josuke lived a pretty relaxed life compared to the journey to Egypt the protagonists from Part 3 had to experience.
Last thing to add is, i said Giorno was the best protagonist of any jojo, and while i still hold that position, he is pretty boring, like, he doesn't stand too much, everyone else in the gang team is funny and entertaining, but Giorno is like "I must accomplish my dream, so i have to be the most serious of the serious, serious", as a Character, he could have been not developed, but at least fleshed out, like, he can't stop all the drug sellers in the world selling said things in the world, he knows perfectly he can't bring Justice to everyone, so why he has that kind of dream when he did not have experiences with drugs?, i'll leave as it is.