For many of today's readers, Wally was the Flash they grew up with since Barry Allen, the original (not counting Jay), died in 1985. It makes sense that with Barry back, having two Flashes in a new universe could be a bit much.
"Merry Christmas to Everyone! Even you Wally. maybe I'll see you in the New Year."
Now this could just be a tease. Dan could be joking. Or maybe with the mention of Garth in AQUAMAN #14, there could be something in the works.
It's likely nothing but we won't give up hope.