Between that, the solicitation copy, and Tempus Fuginaut on the Flash Forward #1 cover, everything seems to be pointing to Wally being infected by the Dark Multiverse, tying in with the Batman Who Laughs/Secret Six storyline.
Back in Flash #55 there was a scene where Barry saw a red blur, followed by an angry zombified version of Wally coming out of the bathroom mirror. At first Barry thought it was one of Mirror Master's tricks, then it vanished. This was after Flash War, but before the Heroes In Crisis tie-in. The story arc was about Heat Wave getting the Sage Force, but there was no follow-up to what Barry saw, no indication that it had anything to do with the Sage Force.
Williamson spoke a bit about Wally's current situation on the Word Balloon podcast:
http://wordballoon.blogspot.com/2019...nd-batman.html (from around 1:39:50)
"We plan this stuff out so far in advance, that it's tough sometimes. Like, there's stuff sometimes you can see, you're seeding things, you're planning things and you know what's coming. It's hard sometimes to tell a reader like, wait, y'know, and hope they can trust you and have faith, and I know sometimes that's really challenging."
"All I can say is that the story's not over."
You know this isn't true. Kid Flash is in Teen Titans, Impulse is in Young Justice, Wally West has a mini-series coming up, Jay Garrick has appeared in Doomsday Clock and will be appearing in an upcoming Justice League story. In terms of villains, there are ongoing sub-plots with Godspeed and Hunter Zolomon in Flash, and an evil (Earth-3?) counterpart of Impulse will be in Young Justice.
Complaining about things that aren't true just drowns out and undermines all legitimate complaints and criticisms.