So if I'm a writer on this show I roll with the Rebirth storyline.
I start by having Wally healed for the finale. Barry is despondent and falling into that dark path. Wally decides that he's not letting it happen and HE enters the speedforce to try to reset everything.
At that point in the episode, I'd have shown Killer Frost wrecking Cisco's hands as well. Barry is despondent. But once Wally goes in, he starts to see things reset. Iris is alive. Cisco gets his hands back, Caitlyn stops being Killer Frost, etc.
Episode ends with Barry, snapping to it, saying, "Where's Wally?"
Joe: "Who's Wally?"
Fast forward to S4. First episode is Wally trying to escape from the Speedforce. Jay sees him and doesn't know him or how to help. He reaches out to the Legends who don't remember him. Cisco doesn't remember him. Arrow/Felicity sense a presence in the cave and nothing. (They can even see a smiley face pin on the floor afterwards if CW will be allowed to roll with Watchmen characters, which I doubt.)
Episode ends with him trying to reach out to Barry, who at this point is convinced by everyone else that there never was a Wally. Just like the comic.
But then he remembers. BOOM. Pulls Wally out and we have Wally back.
End of season 4 premier
That way you can easily pull in Godspeed as one of your big bads for next season. However, you can also have that revealed later on, after they take down Abra Cadabra or something at midseason.
Barry can be trying to open up Star Labs as a place for other speedsters who have popped up. These people can keep disappearing, some dying. Nobody sure why but they're convinced it's Abra Cadabra. Then they finally stop him, only to find out that Cadabra knew absolutely nothing about the missing speedsters. You get the whole fear between Barry and Wally that maybe they didn't kill Savitar, only to realize that it was someone far far worse.
I dunno. It'd be better than this season I think lol