Johnny dies. Reed, who unwittingly played a role in Johnny's death, divorces Sue and leaves the team indefinitely.
But wait, there's more!
Franklin and Valeria get roped into an urgent mission involving Illyana Rasputin and demons from Limbo. When they return -- seemingly a brief instant in our time, but a lifetime in Limbo -- Valeria is 18 years old and Franklin is correspondingly older as well. Valeria has mastered science and magic to the point that the two are indistinguishable. (Dr. Doom finds that out in short order that she is truly a force.) As for Franklin, he no longer has his godlike psionic abilities. The demons captured him and basically lobotomized his mutant telepathic and telekinetic abilities. But he is still able to absorb cosmic radiation and turns into an energy form not unlike the Human Torch with molecular manipulation powers similar to DC's Firestorm.
So...taken all of the above into account, it's time for the Fantastic Four roll call:
Sue Storm, Invisible Woman
Ben Grimm, The Thing
Valeria Richards, Valeria (like a rock star or pop icon, she becomes known by one name only)
Franklin Richards, The (new) Empyrean
Please, please, please, PLEASE make my dream come true, Marvel!!!