One notable thing is that despite the very vocal positive reaction of some fans to the Rebirth/Reborn Superman and family, and an echo chamber in the Internet media, the truth is that those books have not really sold much better than Action Comics and Superman sold during the equivalent New52 years. I think the powers that be may realize that bottom line is book sales, and the book sales for the present teams and direction were only par for the course for the early years of a reboot and would have inevitably declined in the years to come, and decided it was time for another shift in direction.
In a sense, Rebirth was an "overcorrection" to the New52. I actually thought the New52 was great and would have liked to have seen that Superman continue forever, but for the sake of argument let's say there were obviously some fans who felt alienated by the New52. Rebirth swung in an entirely new opposite direction and alienated other fans. Superman Reborn supposedly merged the two Supermen, but the writing afterwards was largely as if it were just the Rebirth Superman. Maybe what Bendis will do is really take the best from both, and from past other directions, and incorporate what he's learned at Marvel and his own special sauce.