I think the editors were probably aiming to showcase the mangaka that were most likely/ready to come back with something new, whether they've had renowned works in the past, or they're among the best of the worst from recent years.
The mangaka of Psyren, Hokenshitsu, Magico and Kagami no Kuni have made works that have at best lasted at least a year, too popular to have been cut to around 20 chapters like most other manga at the time, but not enough to get an anime.
My speculation for something to come out of Kenji Sakaki soon comes from the fact that she's among them too, but also, ignoring Ikezawa whose manga ended just seven weeks ago, the latest mangaka to have accomplished this feat. I only just discovered a few days ago, but apparently, when Enigma started, it ranked high, like 4th or 5th. Maybe I'm being too optimistic, though.