The line distribution was mostly what I was expecting, except there was considerably less Ayumi than I thought there was going to be, but I imagine she will be more heavily featured on the other A-side. I don't see them using Masaki as a Reina replacement really, except for the color change on that one magazine shoot I guess they both have a very idol voice. She's more featured I guess, but it was a good balance between her, Riho, Mizuki and Sakura. I expect to see less of her on the other A-side in much the same way she was not as prominent in Kimi Sae.
Ayumin still had a really prominent position in the video which is something I'm glad to see.
I think if they switch it up with prominent video people and prominent song people blending out the group it'd be great. Ikuta doesn't sing much but her voice is still strengthening so I wasn't surprised to not hear much of her and Iikubo. Of course I'd like 80% more Duu (I freely admit I'm biased) so the song's a bit bitter sweet... I want to hear my oshi but all and all I'm glad to see the girls take a more "group" stance averse to a "soloist/backup' stance.
As far as how things are broken up... I think Osaka Koi no Uta's a good example. You have three different leads, two girls who get a B side, and more lines distributed through the group. Tweaking along those lines (a bit more lines amongst the "chorus" girl section) I think that's my personal favorite division.
I also like how this song is lower in tone than some previous songs. Less squeaky. But I'm not a fan of the high pitched S/Mileage style even when their voices support it for a full tone like Meimi's or Kanyons. Sans Reina and Eri, MoMusu has been a mezzo range and personally that's my favorite. I'm not 100% on the song yet though it's pleasant. I can see the idea of Kimi Sae that people are saying but I think they're more spiritual successors.
I like the electronica though I'm also fine if MoMusu were to try a completely new style again. If Platinum Musume's basis was R&B pop then Colorful Musume seem to be electronica. Though I'd like them to just try something new and weird like metal or jazz or big band or salsa again, too