Yea, I had my issues with the SP too. I really didn't like the narrative they were trying to force down our throats about rivalry being the key element to Musume's success. It starts feeling like some kind of indoctrination camp for the 9ki and 10ki, and they set up Aichan as the fall girl for the group's decline that way.
I've always wanted to see the OG interact more with the current gen, like have favorites, actively root for their success and want to help them develop. I think I had this opinion cause when I started my fandom I was watching H!M where a lot of the OG would still come back and play with the new members even though they had graduated (on Eric Kamezo for example) and I really enjoyed that - like once a Morning Musume, always a Morning Musume, and we're all in it together even if we're not in the current lineup.
I can understand that they want to figure out what was responsible for the success of the past, but there is a real illusion of control that they are suffering from. In the end there was a lot more dependent on the timing, promotion strategies, luck than the rivalry of the 1ki and 2ki (although it is important). So when this program singled that factor out, and each OG said this is what made us great, and each kohai had to swallow that and say this is why we declined, it's a bit absurd.
One thing that left a really bad taste in my mouth was the part where Aichan is talking about becoming leader, and she says I was not sure what I should do but Nakazawa-san told me I should just be my own kind of leader which helped me out a lot. Then they have others talking about Aichan's "at home" feel where the rivalry became minimized and they cut to Yuko saying I didn't agree with the direction Aichan took it, but I wasn't going to say anything because it wasn't my group anymore. It felt kinda two-faced to offer her support and privately badmouth her, and I don't like that for either Aichan or Yuko's sake since I like both of them.
Then at the end when they are talking to the OG, you can see how little they were invested in the current group - Miki and Tsuji say they couldn't name any of the 9ki or 10ki. So you have these girls who don't know anything really about how the current group is, and they are giving the final judgment on how it should be run to Sayu and Reina, so they hand down this to the 9ki and 10ki, and Maachan, Haruka and all start crying cause they are sorry they wronged the legacy of Musume and weren't rivals enough and distant enough from each other.
Well lol, sorry for the rant, but I didn't enjoy the program. Near the end of it, I was more interested in what the fans they were interviewing outside the concert hall had to say than the OG. At least they are still committed to the group and can really talk about what it means for Morning Musume to evolve and grow.