As one of the more hardcore Manofriends here, this announcement comes as a shock but at the same time it's not entirely surprising to me.
Manochan is getting older, hotter, and most of the time it seems like she acts more than sings.
I've been saying for a while now that she's the best, most experienced actress H!P has.
But still, that's not enough for her to have a future as an actress, which is where I think her career has been headed for several years now.
Being an idol puts serious restrictions on the kinds of roles you're considered for as well as what you can do during them.
When Sayu was in that recent cell-phone drama where she plays the promiscuous younger sister of the main character, there were problems on the set with how some scenes could be done.
The way I heard it, she flat out refused to be kissed in a certain scene due to her idol status, which caused some friction with the production staff.
Even though I saw some screencaps of her in a kissing scene and her in bed next to a guy, there's no onscreen lip contact and certainly no sex scene.
In fact, I think the only times I've seen an active H!P member in such scenes have been in lesbian situations... but that's another discussion entirely.
The fact is, Manochan has been becoming like a hybrid actress-idol for a while and idols have an expiration date, but actresses don't.
In order to give her a shot at an acting career afterward, there must be a departure from being an idol.
Given her acting chops, how undeniably photogenic/hot she is, and the recent direction and imagery of her singles, this timing is as good as any.
If she wants to show that she's more than just an idol, the sooner she gets on that the better.
The 7 month lead-up time between announcement and graduation also says to me that this is a deliberate decision and not one caused by any scandal or unexpected circumstances.
If it were, the timeframe is much shorter, anywhere from a day to a couple of months.
Instead, her lead-up time is quite similar to Aichan's, which lets everyone have the proper time to prepare.
Rather than having a random press release out of the blue, making this announcement during the first concert reinforces how intentional this is.
Plus, just as Aichan's graduation the space open for Riho to fill, Manoeri's departure leaves a spot for a new soloist.
When H!P has just a single moderately popular soloist, it's near-impossible to add another one without cannibalizing her market.
In fact, I think this was a big factor in having Kikka debut outside of H!P.
(It was different in the past when all the soloists were pretty popular.)
So basically, I think this is a signal that we may be in for a new solo act.
She may debut soon after Manochan's graduation, a little before it, or possibly even at that concert.
In any case, I believe it will be sometime around her graduation.
As for who it will be, even though I wouldn't bet on it, I still have my fingers crossed for Karin.
So basically, it comes down to this.
1. Manochan needs to leave behind being an idol in order to pursue her acting career, which she's shown considerable talent for.
2. 7 months forewarning means this is a deliberate decision, not one brought on by any unexpected event.
3. Having her graduate leaves space for a new, younger soloist to have her chance.