Jo Eriko refuses promotion to Team M, stays as NMB Kenkyuusei
I am disappoint.
Jo quit a while back to focus on "studies" but at the same time she also said "we might see her again when she's more grown up."
Remember that Jo was pretty damn popular and had a lot of Acchan-esque charm. She could've been huge.
In other words, she couldn't handle the pressure so she quit. Understandable, since she was like 13 years old at the time. Can't blame her.
However! This is a different situation.
Jo got a lot of hate for being promoted so early after her return. You could argue that's fair since the other girls and KKS have been working their ass of the past year. On the other hand, Jo was a proper member when she quit so one could assume she has the abilities it takes to be a proper member already. If she has the level, why would it be bad to promote her back already? Similar case for Suzuki Shihori, really, except Jo is/was more popular.
The second issue is her potential rivalry with Fuuko, who in essence took over the next gen ace role from Jo. Now that's back, in the same team no less, how is that gonna play out? This new dynamic caused by the new group line-up could have worked greatly to NMB48's advantage as well. It never hurts to have more aces in one team/group.
Long story short, Jo has to deal with bitching from fans about her quick promotion, as well as new rivalries. To me it looks like she just quit again because she doesn't want to or cannot deal with it.
If you truly aspire to be a great idol, which Jo has/had every potential too, you can't walk away from opportunities like this. Jurina would never refuse promotion or a kennin position. Anything to get your name out there and to get the best spots on stage. (Jurina may be too extreme, but as an example she works very well). The age argument isn't valid anymore either since she knew exactly what she was getting into. I guess Jo just wants to be a big fish in a small pond.
So yeah, that's the last we'll ever hear from Jo. Congrats Fuuchan.