I've learned not to set too many expectations or get too invested in speculating about comics that aren't out yet. I feel like that's where a lot of the outrage in comic book fandom comes from these days, and I just don't want to play into that.
We don't know much about the series yet. There are black doors appearing around the world which seem to mirror Wanda's Last Door; Vision is going to be mortally wounded in the first issue; and the Grim Reaper is there. In a recent interview, Orlando specificaly refers to the doors as "Death's Door," and the solicit for #3 states that Wanda and Vision will travel to someplace called the "Graverealm," which, as far as I can tell, is a new setting.
The Grim Reaper is apparently connected to Death's Door, but I doubt that he's the mastermind here. I expect that his role will be similar to the Wizard's-- some kind of herald or pawn for a much greater antagonist. In the preview pages, he seems to be wielding some kind of dark magical power against Vision. I'm guessing that Vision will be critically injured in this fight, and Wanda will heal him, which is when he'll turn white. I assume that there will be some other side-effect, but I doubt that it will be the same as last time.
I'm very curious about this "Graverealm." There are already counltess afterlife realms in the Marvel universe, and I feel like it would be redundant to add another one so shortly after re-vamping the Land of the Dead/Witches' Underworld. All I can say is that I hope it's something a little more unique. I do wonder if this exploration of life and death create new avenues for Vision to examine how he defines his own humanity and state of living. The interview also mentions that we'll see how Vision feels about his relationship with Billy and Tommy, or lack thereof. I don't know if we can expect them to actually show up, but I do hope so.
Beyond that... altogether, this series has been running for over two years now. Orlando's done a great job of bringing new characters and concepts into Wanda's world, but I'm ready for him to start doing more with what's already there-- like how the Last Door has changed and revealed new functions over time. I want to pick up some the loose threads with characters like Lore, Nicholas, and Hexfinder; I want to spend more time in settings like New Salem, the Witches' Road, and Planet Amanna. Wanda's world would feel much richer and more immersive if some of this stuff could just sit and marinate for a while.