As Shiori said in her interview with TGU, 'we can't go on like this'. They're stagnant for the last few years in terms of popularity, so things probably are going to change.
* They're all adults now, so it's probable they have a bigger vote in the musical direction than before. With at least 5 pop girls in the group, it's not hard to guess what that direction will be.
* They're looking for a broader target audience (aka girls) -> resulting in dance versions, gpp's, and cuter songs.
* On the other hand, they have a producer/main composer whose influences are firmly rooted in 80's/90's western (hard)rock.
Resulting in songs where he tries to make everyone happy I guess, but that sound forced/messy/cheesy imo.
About "Not in Theory" I'm not sure if Kentaro is writing songs for Band Maid (I know he produced 2 of the songs on the CD) but it sounds more like a Band Maid song than a PASSPO song, in fact I don't think it suits PASSPO at all.
Yes, these 2, Thrill and Shake that, he composed them as well.
I agree NiT is (almost) heavy metal so more in style with Band Maids album, but what does suit Passpo and what doesn't? HTE is very untypical but a lot of fun imo, Fairy Tale sounds more like Predia... (and Predia's Kiss Kiss Kiss that he also wrote sounds more like Palet, and so on...)
It's not that Passpo has a clear cut musical direction. Please let them try new things, with mixed results.
There are loads of idol songs that don't suit the group that performs them (making them sound almost exactly like another group). Is that a problem or part of the charm of the genre? I think the latter.