The reason why Urobuchi probably thought Jounouchi was a character would appeal to adults probably lies in his tirade to Oren who was trying to train him. Jounoichi is aware that he is a fake and a charlatan but doesn't know what to do with his life which is why he can't be like Oren who is filled with conviction and resolve towards his craft as well as disciplined enough to become strong in the military and whatnot. Though Oren later tells him that being an adult doesn't necessarily mean knowing what to do with your life and whatnot, stating that everyone is just as equally confused and worried about their future, but that they have to go through with it. Urobuchi probably thought that adults would relate to him because Jounouchi is an outsider, weird even among his dance team contemporaries, and with the loss of Hase, the dissolving of the dance stages and whatnot, he was just meandering around looking for a purpose.
I was actually really pleased at how the episode turned out. It was wacky, but Urobuchi managed to intertwine the episode and Oren/Jounochi's development with the whole growing up theme at Urobuchi mentioned at the beginning of the season. It was a pretty necessarily filler I think for Jounouchi. Gives closure to him so he's not just dangling there at the end of the season.
Many people predicted we would have a Forbidden Fruit-esque plot and they were right. Sagara states that he's an observer, but also states that favoring Kouta isn't fair and tell him that whatever power they are searching, lies with the Overlords and suggests to Ryouma and co. to seek them out, which is exactly what he told Kouta to do albeit under different pretenses. It's interesting to note that he's pushing both Kouta and Ryouma's faction to find to Overlords, which will surely lead to an inevitable confrontation between the the two. And of course, Takatora probably isn't sitting idly here either so he'll definitely been in on the action as well whilst Michi snaps.
People have mentioned that Sagara is like the Biblical snake that tantalized Eve with knowledge within the Garden of Eden, and that's exactly what's happening before our very eyes in Gaim. The fruit probably does provide God-like power and ascension from their current mortal state, but what the power will be used for is up to the user. The Rider Sengoku Era might in fact be for the power of the Forbidden Fruit.
Sagara is Kougami done right! Thus far!