One of the thing that kind of annoys me with that manga is that at first, it was "whoa, Vivio have an adult mode that she can control", like it was something unique. Then Ein came in with one two, but well, she was somehow related to Vivio, so why not...
But then, even Vivio's friend had one because... reasons ? And now, it seems pretty much every loli character out there can turn into an adult as they want. Kind of annoying, really...
A shame, because I really like Vivio as a character (only thing that made Strikers barely worth watching in my opinion), but this manga is kind of ruining both her and the whole setting to me. :/
Think I'll stick with my rule of "there's nothing after nanoha A's." ><